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1. A new diagonal etectrophoretic technique for determining the order of the lysine-containing tryptic peptides of a protein is described. The protein is converted into its trifluoracetyl derivative, digested enzymatically (or chemically), and the resulting peptides separated by paper electrophoresis. The paper is then treated with ammonia vapour, which re-exposes the ε-amino groups of the lysine residues, and submitted to a second electrophoresis at right angles to the first direction. Peptides containing lysine residues, together with the N-terminal peptide of the protein, are found to lie off a diagonal formed by all other peptides, whence they may be readily purified. A study of these peptides enables the order of the lysine-containing tryptic peptides in the protein to be deduced. 2. The technique has been successfully tested with insulin. 3. When the method was applied to porcine pepsin, the four tryptic peptides isolated were easily ordered and the carboxyl-terminal sequence of the protein shown to be Arg-Gln-Tyr-TyrThr-Val-Phe-Asp-Arg-Ala-Asn-Asn-Lys-Val-Gly-Leu-Ala-Pro-Val-Ala. The thee basic ammo acid residues in the molecule are thus found clustering towards the C-terminus of the polypeptide chain. 4. A common ancestral gene for porcine pepsin and bovine (calf) rennin is suggested by the close homology between the C-terminal sequents of the two proteins. [ABSTRACT FROM AUTHOR]

This article discusses paper electrophoresis patterns of enzymes involved in polyglucoside synthesis in oscillatoria princeps and its low temperature strains. The technique of paper partition chromatography and paper electrophoresis for the study of genetically different tissues have recently found application in the field of genetic studies. These methods should prove of considerable interest in the detection of differences between enzymes having the same properties and functions in the different species.

Paper chromatographic determination of amino acids separately from the embryo and endosperm of rice (Oryza sativa L.) during germination and seedling growth without added nutrients for 8 days has been made. After different hours of germination the endospermic protein is hydrolysed and other amino acids appear and are translocated to the embryo. Arginine, tryptophane, tyrosine and ornithine are detected in the embryo during its growth but absent in the endosperm. Their appearance in the embryo is suggestive of interconversion by transamination. [ABSTRACT FROM AUTHOR]

A purified glycoprotein with blood-group-A specificity, was digested with insoluble pronase to give a serologically active product enriched in peptide-bonded serine and threonine residues; this was degraded with 0.25 M sulphuric in glacial acetic acid for 24 h. The resultant N-acetylgalactosaminyl-peptide were hydrolysed with 0.2 M hydrocholoric acid for 24 h at 110 °C. fractionation of the products on Sephadex G-10, followed by preparative separation on amino-acid analyzer and paper electrophoresis at pH 1.9 yielded the following homogeneous oligopeptides; one tripeptide with the N-terminal sequence Thr-Thr-Ser, three tetrapeptides with the sequences, Thr-Ser-Thr-Ser, Thr-Pro-Thr-Ser and Pro-Thr-Thr-Ser, one pentapeptide with the sequence Thr-Pro-Thr-Ser, one hexapeptide with the sequence Pro-Thr-Thr-Thr-Pro-Ser and one heptapeptide with the sequence Ala-Pro-Thr-Thr-Ser-Gly-Ser. Galactosamine was present in several of these fragments and the hexapeptide and heptapeptide both contained sufficient of this sugar for all the serine and threonine residues to be glycosylated. The following five tetrapeptides sequences were deduced from mixtures of two peptides which differed by the amino-acid substituent at only one position in the chain; Pro-Thr-Ala-ser, Thr-Thr Pro-Ser, thr-Thr-Ala-Ser, Ser-Pro-Thr-Ser, and Ser-Ala-Thr-Ser. A tripeptide mixture which differed only in the nature of the third amino acid yielded the following three tripeptide sequences: Pro-Thr-Ser, Pro-thr-Ala. These peptides do not indicate a clearly defined amino-acid sequence surrounding the glycosylated hydroxy amino acids but establish that in the human blood-group-specific glycoproteins there is close packing of the threonine in the region of the peptide moiety carrying the carbohydrate chains. [ABSTRACT FROM AUTHOR]

1. The enzyme preparations tested for cellulolytic activity were from pure cultures of Streptomyces sp. QM B 814 and of four different Hymenomycetes, viz. Polyporus annosus Fr. and three strains of Collybia velutipes (Curt. ex Fr.) Quéll, i.e. two monocaryotic wildtypes L 1 and L 11, as well as the dicaryotic combination (F 29/157 X F 28/42) between two arginineless mutants. 2. The enzyme activity against cellulose sol has been measured turbidimetrically, the method being referred to as the photometric method in earlier papers. (Norkrans 1950 a, b). The activity has also been expressed in terms of reducing substances, glucose formed, and changes in average degree of polymerization (DP). Furthermore the enzyme attack has been studied by electron microscopy of the cellulose sol. 3. In all tests the preparation of Collybia velutipes (F 29/157 X F 28/42) showed the greatest total activity as well as the highest reaction rate. 4. According to the turbidimetrical readings, as to the DPn-determinations, the enzyme preparations had a great influence on the cellulose sol during the first hours of incubation. The Z-values increased rapidly, after the first twenty hours representing 60 to 90 per cent of the end-Z-values. The initial DPn-value of 338 decreased to 50-60 in four (or six) hours. 5. The paper chromatogram indicates the presence of cellobiose as well as another, slower-moving substance, presumably cellotriose, as breakdown products besides glucose. 6. A comparison between the DPn-values and the corresponding glucose values lend support to the theory of a random-splitting of the cellulose chain. 7. Expressed in terms of reducing substances, the breakdown did not in any case proceed to more than about 65 per cent of the total initial amount of cellulose. The polymerization seemed to proceed until a DPn of about 50. These limits seem to be related rather to the morphological structure of the cellulose sol particles than to the enzyme inactivation. Electron micrographs of such cellulose residues lend support to this conclusion, since they revealed a mass of distinct and fairly homogeneous particles about 300 Å long and about half as wide. These stood in clear contrast to those of the untreated cellulose sots, containing larger aggregates of longer disordered fibers forming an irregular network or unresolved lumps. [ABSTRACT FROM AUTHOR]

Peptide studies on two acidic proteins, A1 and A2, from 50-S ribosomes of Escherichia coli indicate a closely related primary structure. 1. Amino acid compositions of the tryptic peptides of the two proteins are identical, with exception of the amino terminal peptide. 2. The N-terminal amino acid sequence of A2-protein is Ser-Ile-Thr-Lys, while that of A1-protein is N-acetyl-Ser-Ile-Thr-Lys. 3. The estimated number of 120 amino acid residues in each polypeptide chain is consistent with the physical molecular weight estimate. 4. In 50% of the polypeptide chains, in both A1- or A2-protein, a specific lysine residue is replaced by ε-N-monomethyl-lysine. [ABSTRACT FROM AUTHOR]

Examines the technique for immunoelectrophoresis. Performance of immunodiffusion in the strips; Separation of protein fractions by thin layer chromatography; Use of cellulose acetate in the method.

Semliki-Forest-virus 42-S virion RNA is translated in a mouse ascites cell-free system. One of the major polypeptides made in vitro has been identified as Semliki-Forest-virus capsid protein by co-electrophoresis on dodecylsulfate -- polyacrylamide gels and by tryptic peptide analysis on paper. Another major product of the cell-free system has been characterised as envelope protein by peptide analysis but it does not co-electrophorese on gels with envelope proteins from purified virions. It is possible that the nascent, non-glycosylated polypeptide is partially degraded by proleolytic enzymes present in the cell-free extract, or alternatively that fragments of envelope protein are produced by premature termination on the viral RNA. Several other polypeptides are synthesised in the cell-free system in variable amounts but these have not been identified. The genetic content and the mechanism of translation of Semliki-Forest-virus 42-S RNA are discussed. [ABSTRACT FROM AUTHOR]

I. This paper describes some features of the protein synthesis in isolated rat liver mitochondria and reports on the stability of the product of mitochondrial protein synthesis in vitro. 2. Chase experiments performed after a 30-min pulse of [14C]leucine indicated that a large part of the product is degraded to an acid-soluble form (labile product) almost as rapidly as it is terminated and released from the mitoribosome. Only a small proportion of the completed product (between 20 and 40 %)is conversed in acid-insoluble form (stable product). 2. Both labile and stable products have an exceptional degree of hydrophobicity, shown by their marked resistance to acid and alkaline hydrolysis and by their solubility in organic solvents. 4. A 14C-labelled peptide with an apparent molecular weight of 12000-13000, as assessed by gel electrophoresis in the presence of dodecylsulfate, is released after heat treatment of mitoribosomes isolated from mitochondria pulsed with [14C]leucine. [ABSTRACT FROM AUTHOR]

With the help of an automatic protein sequenator, we have verified a prediction made by us in a recent paper, namely that residue 16 in Candida krusei cytochrome c is a glutamine and not a glutamic acid. Neurospora crassa cytochrome c now remains the only mitochondrial cytochrome c which apparently does not have a glutamine at this position. In the course of this investigation, from two strains of Candida krusei we isolated two cytochromes which differ in amino acid composition. One of them seems to correspond to that described in the literature. Two of the differences have been located. [ABSTRACT FROM AUTHOR]

The globin of sheep heart myoglobin was first cleaved by cyanogen bromide and the resulting fragments were fractionated by gel filtration and preparative paper electrochromatography; each fragment was submitted to endopeptidase digestion and the complete amino acid sequence has been determined. The intact globin and the median cyanogen bromide peptide were analysed by the protein sequanator (Edman). This analysis confirmed the sequence of the first 46 N- terminal residues of the intact globin and established the sequence of the first 39 N-terminal residues of the median cyanogen bromide peptide. Between sheep and beef myoglobin six differences over 153 residues can be noticed; among the six amino acid replacements, two correspond to the exchange of two bases and four to the exchange of one base in the coding triplets. [ABSTRACT FROM AUTHOR]

Reduced and carboxymethylated thioredoxin H from Saccharomuces cerevisiae was digested with trypsin and cleaved with cyanogen bromide in Separate experiments. From the amino-acid sequences of isolated peptides after chymotryptic or peptic hydrolysis an alignment of a 17-residue sequence around the redox-active disulfide of thioredoxin II was possible as follows: -Phe-Ala-Thr-Trp-Cys-Gly-Pro-Cys-Lys-Met-Ile-Ala-Pro-Met-Ile-Glu-Lys- Comparison of this structure with the corresponding amino-acid sequence of the thioredoxin from Escherichia coli B showed identical residues in 10 consecutive positions which included the tryptophan residue, the disulfide ring and the five residues following this on the COOH- terminal side. The COOH-terminal sequence of yeast thioredoxin II was: -Glu-Ala-Ile-Ala-Ser-Asn-Val and the NH2-terminal residue was valine. The sequence results indicated a considerable homology in primary structure between yeast and E. coli thioredoxins and suggested the existence of a common ancestral gene for thioredoxins. The sequence of a peptide from the active site of yeast thioredoxin I showed that the structure around the disulfide bridge was: -Tyr-Ala-Thr-Trp-Cys-Gly-Pro-Cys-Lys-. This indicated that thioredoxin I and II from yeast have different primary structures. [ABSTRACT FROM AUTHOR]

A model is proposed to explain the biphasic reduction of ferricytochrome c at alkaline pH assuming an equilibrium distribution between a reducible and non-reducible conformer. An analysis of this model is given in an appendix to this paper. Protein denaturants, increasing pH and temperature are found to disturb the conformer equilibrium in favour of the irreducible form. The thermodynamic parameters governing this equilibrium have been determined. Kinetic parameters defined in the model were measured under a variety of conditions. The kinetic and equilibrium data strongly suggests that only the reducible conformer possesses the 695 nm band. Possible origins of the 695 nm band are discussed. [ABSTRACT FROM AUTHOR]

Two isogenic derivatives of Escherichia coli K12: strains EA 1 (Met-, Biot-, RCstr and EA 2 (Mei-, Biot-, RCrel) when grown in the presence of ethionine in place of methionine, synthesize ribosomes whose RNA is submethylated and whose proteins contain ethionine. Net ribosome synthesis in the presence of ethionine is greater in the RCrel strain than in the RCstr strain. The precedinig paper describes results obtained with the latter strain. Here we present further studies carried out with the isogenic RCrel strain EA 2 As in the case of the RCstr strain (previous paper) ribosomes synthesized by the RCrel strain grown in the presence of ethionine display defective association properties. A large fraction of these "ethionine" ribosomes is found as free subunits in crude extracts containing 10 mM Mg+ prepared from strain EA 2 grown in an ethionine-containing medium. These free "ethionine" subunits have sedimentation coefficients of 28 S and 45 S approximately while the "ethionine" subunits found associated as 70 S particles in crude bacterial extracts sediment at 30 S and 50 S respectively. Both classes of "ethionine" subunits (free, and associated) can be methylated in vitro in the presence of S-adenosyl methionine with or without the addition of an external source of methylases (100000 x g supernatant of a homologous crude bacterial extract) The latter observation shows that the "ethionine" subunits contain bound methylases. These enzymes do not seem to be normal ribosomal proteins nor to be bound specifically to "ethionine" ribosomes since (a) they are removed by washing the "ethionine" ribosomes with 1 M NH4Cl, and (b) they are found bound to normal methionine ribosomes from which they are also removed by washing with 1 M NH4Cl. [ABSTRACT FROM AUTHOR]

The partial specific volume of chymotrypsinogen A in water and aqueous urea solutions has been determined from density measurements. The partial specific volume of the protein first increases with urea concentration, reaches maximum, decreases, reaches minimum, and then increases again. An interpretation of this behavior has been attempted considering especially the binding of urea to the protein and imperfect atomic packing in the native protein. From dilatometric experiments the differences between the partial molar volumes of the protein in water and urea solutions of different concentrations, respectively, have been obtained. The agreement of the values of these differences with those calculated from the partial specific volumes is satisfactory. It can be seen that the volume changes reflect the interaction of urea with the protein which eventually results in complete unfolding, i.e., denaturation, in about 8 M urea. Subsequent papers will deal with further aspects of this denaturation. [ABSTRACT FROM AUTHOR]

400 fold purification of GDP glucose pyrophosphorylase from pea seedlings concomitant with stabilization of enzyme activity has been accomplished by (NH4)2SO4 fractionation, followed by chromatography on Sephadex G200 and DEAE-cellulose columns. In this last step the enzyme is eluted with 0.20 M NaCl. The enzyme is specifically activated by Mn2+. The apparent Km value for glucose-1-phosphate (37°, pH 7.5) is about 3 × 10-4 M. The GDP glucose biosynthesis is found to be reversible, with the equilibrium in favour of pyrophosphorolysis. The purified enzyme is not active with GTP plus mannose-1-phosphate or galactose-1-phosphate. No formation of nucleotide sugar is observed in the presence of glucose-1-phosphate plus ATP, ITP, dTTP, or CTP. A small residual UDPG pyrophosphorylase activity is activated by Mg2+. [ABSTRACT FROM AUTHOR]

We have further characterized the polynucleotide ligase purified from cultures of the human heteroploid line EUE [Spadari, Ciarrocchi and Falaschi, Eur. J. Biochem. 22, 75 (1971)]. The 350-fold purified enzyme gives positive response with four different assays; the rates with the different substrates are different, but the variations are identical to those observed with the purified ligase induced by T4-phage. The enzyme can reconstitute the transforming activity of Bacillus subtilis DNA inactivated by pancreatic DNAase. The human cell enzyme is unable to use a hybrid substrate where an interrupted polydeoxynucleotide is annealed to a polyribonucleotide, whereas in the same conditions the T4 enzyme gives appreciable activity. The partial dependence of the purified enzyme on proteins present in a boiled crude extract, reported in the previous paper, seems due to an aspecific protective effect of the soluble proteins of cell extracts. The enzyme does not show any appreciable sequence specificity in the phosphodiester bond it can form. The purified enzyme can be fractionated into two molecular forms, one having a molecular weight of 190000, the other 95000; fresh extracts of EUE cells contain almost exclusively the high molecular-weight form; ageing of the extract or purification lead to the appearance of the second peak, without variations in the total activity. This could correspond to the conversion of a dimer structure into a monomer. The “dimer” has a pH optimum close to 8.1, whereas the “monomer” has its optimum at 7.5; this explains the bimodal pH curve previously described in the purified enzyme. [ABSTRACT FROM AUTHOR]

Binding of tryptophan, tryptamine and ATP to tryptophanyl-tRNA synthetase was studied by equilibrium dialysis experiments. There arc two binding sites per mole of enzyme both for tryptophan and for tryptamine. Ks for tryptophan is 0.95 μM and for tryptamine is 1.8 μM. In the case of ATP no binding could he measured over the range of concentrations examined. The Scatchard plots of tryptophan and tryptamine binding do not shown any cooperativity between the subunits. Dissociation of the dimeric enzyme was studied at very low protein concentration. Upon dilution of the enzyme both the [32P]PPi-ATP isotope exchange activity and the tRNA charging activity are lost simultaneously. Kinetic evidence demonstrates that the inactivation is primarily due to the dissociation of the active direct into inactive monomers. The dissociation is strongly promoted by alkaline pH and is inhibited by the presence of tryptophan or tryptophanyladenylate but not by that of tRNA. The dissociation constant of the dimer-monomer equilibrium at pH 8.5 is 15 nM at 25 °C. The dissociation form is more susceptible to denaturation than the dimeric species. The results reported in the paper suggest that even if there are not binding interactions between the subunits, the active conformation of the enzyme depends on their associated state. [ABSTRACT FROM AUTHOR]

The αA2 chain of bovine α-crystallin was fragmented by means of cyanogen bromide treatment and by tryptic, chymotryptic and thermolytic digestions. Twenty tryptic peptides were obtained from the S-aminoethylated αA2 chain, accounting together for the complete sequence. The direct Edman degradation and the dansyl-Edman technique were used to determine the sequences of the tryptic peptides. The order of the tryptic peptides was deduced from overlapping peptides obtained by cyanogen bromide treatment, tryptic digestion of the maleylated chain and chymotryptic and thermolytic digestion of the S-aminoethylated chain. The sequence of the αA2 chain comprises 173 residues and corresponds to a molecular weight of 19832. [ABSTRACT FROM AUTHOR]

In the accompanying paper, we present evidence to show that the biosynthesis of the two characteristic polypeptide constituents ‘A’ and ‘B’ of the crystal protein toxin of Bacillus thuringiensis car. tolworth, is restricted to a short interval, from 16–18 h, in the mid-stationary phase of the growth cycle of 24 h in culture. Here we examine the question of the kinetics of biosynthesis of the corresponding crystal protein messenger RNA. We have taken the direct, approach of assaying a series of RNAs isolated from B. thuringiensis cultures at varying times of culture for messenger activity in a heterologous Escherichia coli, subcelular system. The product of RNA-stimulated protein synthesis in vitro was characterized by immunoprecipitation with anti-serum against purified crystal protein and by polyacrylamide-gel electrophoresis of the antigen-antibody precipitates dissolved in the detergent sodium dodecylsulfate. RNA from B. thuringiensis, but not that of Bacillus cerens, stimulates the synthesis of protein which specifically precipitates with crystal protein antiserum. The time of extraction of RNA from B. thurinrjgiensis does not appear to be critical in determining its messenger activity : all samples taken in the interval of 11–20 h contained messenger RNA for crystal protein by the criterion of specific immunoprecipitation. In each case a significant proportion of the synthesized protein migrated in the region of the smaller-molecular-weight component A (55000) of the crystal protein in the electrophoretic separation. However, hardly any synthesized protein co-migrated with the larger-molecular-weight component B (120000) of this protein. Since all the labelled protein precipitated by the crystal protein antiserum was larger than about 15000 molecular weight we conclude that mainly large fragments of the crystal protein were synthesized in the E. coli system. We failed in our attempts to isolate polysomes as a source of messenger RNA from stationary-phase ceils. Thus it was not possible to determine by experiments similar to those described above whether the crystal protein messenge is stored in ribosomes or in some other fraction of the cell when it is not being translated. [ABSTRACT FROM AUTHOR]

The activities of five enzymes were determined by flurometric micromethods on epidermal tumors (basal and squamous cell epithelioma, keratoacanthoma and verruca seborreica) and compared to the activities in the adjoining, apparently normal epidermis. All activities were higher in the tumoral tissues. [ABSTRACT FROM AUTHOR]

The study of the structure of the peptides arising from native, oxidized or reduced and maleinized bovine growth hormone on incubation with trypsin, ehymotrypsin and pepsin is reported. The data obtained permitted the assembly of a unique sequence of amino acids for the poly-peptide chain of the protein. Various corrections and one addition to the sequence previously communicated are made. [ABSTRACT FROM AUTHOR]

In order to ascertain the physiological role of the peptides which enhanced, the growth of Streptococcus thermophilus in milk, fourteen stimulating peptides were isolated and purified and their qualitative amino-acid composition was determined. The purification process was the following: after hydrolysis at pH 7.5 of whole casein by the neutral protease from Micrococcus caseolyticus the stimulating peptides were fractionated by gel chromatography (Bio-Gel P6), by column chromatography on cation-exchange resins AG 50W X2 (0.05 M pyridine-formate buffer at pit 3.10 to 1.5 M pyridine-acetate buffer at pH 5:10). Further purification was made by column chromatography on anion-exchange resins AG1 X2 (0.1 M pyridine-acetate buffer of pH 7.5 to 6 M acetic acid with a concave gradient system) and by paper chromatography (solvent: butanol-acetic acid-water, 4:1:5, v/v/v) and high tension electrophoresis (30 min; 60 V/cm). Gel filtration of enzymic digest of the whole casein led to six peptide fractions. Three fractions were stimulatory and exhibited a mean molecular weight of (B) 2500, (C) 1500, (D) 1000. Fraction C was the most stimulatory. Three other fractions were inhibitory and contained the highest molecular-weight peptides (about 5000) and peptides with high contents of aromatic residues. Ten and twenty peptide fractions were isolated respectively from Fractions B and D by chromatography on ion-exchange resins; but the peptides obtained after further purification were no more stimulatory. Eleven stimulatory and two inhibitory fractions were separated from Fraction C by column chromatography on cation-exchange resins. Purified stimulatory peptides were obtained from two fractions (C1 and C42) only, after anion-exchange resins (three peptides from Fraction C42, eleven peptides from Fraction C1). These fourteen purified stimulatory peptides display a very variable qualitative amino-acid composition. The polar part (Lys, Glx, Asx) was as important as the hydrophobic part (Pro, Leu, Val, Ala, Gly). The number of distinct amino-acid residues from one peptide was also quite variable: fourteen to four residues. Only lysyl residue was present in all peptides and tryptophan was not present. Three peptides that contained cysteine were issued from %-casein [18]; two peptides (C1a2α and C1C3) could be located respectively to Ala26…Gln22… and Ile26… Arg119 regions from bovine αs1B casein. A complete mixture of amino acids exerted growth stimulation. The set of the amino acids present in a stimulatory peptide was always stimulatory. These data substantiate the following conclusions: (a) stimulatory peptides acted as amino acid source; the amino acids have to be supplied in specific proportions in order not to disturb the cellular amino acids pool and the regulation of amino acid synthesis by Str. thermophilus; (b) the requirements in the peptide-length residues and lysyl residue could be explained by a control system of peptide intake, for example, by a peptide-transport system that would differ from that described in Escherichia coli. [ABSTRACT FROM AUTHOR]

This paper describes the isolation and purification of two RNA polymerases (CI and CII) and several protein fractions (A, B and C) from the chromosomal acidic proteins of coconut endosperm nuclei. The method involves disruption of isolated nuclei in dilute salt medium, centrifugation to sediment the crude chromatin, solubilization of chromatin in concentrated salt, dialysis of soluble chromatin to dilute salt to precipitate DNA-histone complex and centrifugation to get the acidic proteins in the supernatant. Further purification involves ammonium sulphate fractionation and chromatography on DEAE-cellulose and QAE-Sephadex. RNA polymerase CI purified through the QAE-Sephadex step gives a single band on polyacrylamide gel electrophoresis. In gels containing dodecylsulfate, this enzyme shows multiple bands indicating its subunit nature. The pH optima for both RNA polymerases is 8.0. RNA polymerase CI is maximally activated by Mn2+; while CII, by Mg2+. The activities of both the enzymes are stimulated by fraction B. All the fractions except A are substantially free from nucleases. Both RNA polymerases require the addition of DNA for activity. Fraction B is ineffective either with denatured coconut, DNA or native γ DNA. [ABSTRACT FROM AUTHOR]

The isolation of oligosaccharides produced by the action of phage-induced enzymes on the bacterial exopolysaccharide colanic acid is reported. The products from colanic acid produced by different strains of Escherichia coli and Salmonella typhimurium were hexasaccharides which differed in their acyl substituents. All contained fucose, glucose, galactose and glucuronic acid in the molar ratio 2:1:2:1. They appeared to have the same carbohydrate structure as that postulated for the repeating unit of colanic acid. All the hexasaccharides contained acetate. Pyruvate was also found in most preparations. The phage-induced enzymes only converted 30-35 % of the polymer to oligosaccharides. They also hydrolysed de-acetylated polysaccharide but, were inactive against carboxyl-reduced material and against a number of other bacterial exopolysaccharides. [ABSTRACT FROM AUTHOR]

The analytical active-enzyme-centrifugation method permits the determination of the hydrodynamic properties of enzymes while they are fully active on their substrates: the centrifugation can be performed at the very dilute concentrations used in kinetic studies (&aysmp; 1 µg/ml): furthermore a purified enzyme preparation is not necessary and in many cases a crude extract is sufficient. This method is beginning to be used in several laboratories even though few of its experimental aspects have been published. This paper reports the details for carrying out, an activeenzyme-centrifugation run, discusses the experimental conditions anti details with artifacts and ways, which are easy, to overcome them. [ABSTRACT FROM AUTHOR]

The Cbl-1 mutant of Bacillus subtilis 168 WT is the result of a spontaneous mutation presenting a pleiotropic character. In this paper, the results of the morphological and chemical analyses of the cell walls isolated from both strains are compared. When either the whole cells or the isolated cell walls of both strains were fixed with osmium tetroxide, the examination by electron microscopy showed extensive morphological differences in structure due to the partial destruction of the mutant cell walls. The chemical investigations performed on the isolated cell walls revealed surprising differences in chemical structure. In the cell walls of the mutant, teichoic acid was completely missing and was replaced by protein. A major protein-containing fraction accounting for about 50% of the material solubilized by autolysis of the mutant cell walls was isolated. Polyacrylamide gel electrophoresis showed that this fraction was composed mainly of a single protein of high molecular weight When denatured by sodium dodecyl sulfate treatment in the presence of β-mercaptoethanol, the protein yielded by gel electrophoresis two major bands with molecular weights of approximately 105000 and 155000, respectively. The molecular weight of the Cbl-1 cell wall protein determined by high speed sedimentation equilibrium was 255 600. [ABSTRACT FROM AUTHOR]

Semihemoglobins α and β are derivatives of human hemoglobin which possess the usual chain composition (α2β2 or αβ) but which carry the heine prosthetic group on only one kind of chain (α or β), the complementary chain (β° or α°) being heme-free. In this paper, new results on two compounds of this type, namely, semiHbαD (αβ°) and semilHbβ (α°β) have been presented; existing data on other earlier preparations have also been reviewed. Methods for preparation of semiHbαD and semiHbβ have been described-. Some of their properties including optical absorption, circular dichroic spectra, oxygen equilibrium and kinetics of carbon monoxide binding have been measured; these properties are then compared with those possessed by intact hemoglobin (β2β2), isolated chains (α,β) and the berne-free apoprotein (α°β°). 1. The contribution of the heine moiety to the optical absorption and circular dichroic spectra of the semihemoglobins are found to be intermediate between those of hemoglobin and those of the corresponding isolated chain. This result indicates that the effect of interaction between the unlike chains of these molecules are transmitted as far as the heine prosthetic group. The structure of the heme-free chain is also modified as the result of this interaction as revealed by titration of sulfhydryl groups, although circular dichroic spectra in the far ultraviolet are not conclusive. 2. The oxygen affinity and the Bohr effect of the semihemoglobins are again intermediate between those of hemoglobin and isolated chain, the semiHbβ being closer to hemoglobin than semiHbαD. The same is true concerning the velocity of carbon monoxide binding. 3. The kinetics of fixation of carbon monoxide to semihemoglobins is strongly biphasic. It is suggested that this property could reflect the existence of semihemoglobins as two types of filmers (αβ) but differing among themselves on account of different contact regions brought into play. (α1β1 and α1β1 in the nomenclature of Perutz.) 4. The significance of the fact that semiHbα is obtained in multiple forms is considered. 5. The ensemble of the results are discussed in the context of chain-chain interactions. [ABSTRACT FROM AUTHOR]

The substrate specificity of the sorghum acid protease was elucidated using synthetic peptides and pancreatic ribonuclease A as substrates. These studies revealed that the enzyme has a rather narrow and novel specificity requirement. The protease specifically cleaves the peptide linkages involving the α-carboxyl group of either aspartic acid or glutamic acid with the release of the acyl portion of these acidic amino acids. Further, the side chain carboxyl groups of aspartic acid arid glutamic acid in the peptides should be unsubstituted for the enzyme to act on the peptide, and therefore, glutaminyl and asparaginyl peptides are not cleaved by the enzyme. Studies carried out with performate oxidized ribonuclease and ribonuclease methyl esters have further substantiated the results obtained with the synthetic substrates. These results suggest that the sorghum acid protease will be very valuable in sequence analyses of proteins. [ABSTRACT FROM AUTHOR]

Further evidence is presented in this paper concerning the occurrence of three different molecular species of acetyleholinesterase in the electric eel's electric organ. These species, A, C, and D, differ in their sedimentation coefficients (8.5 S, 14.2 S, and 18.4 S, respectively). We show that the whole of the tissue acetyleholinesterase activity can be solubilized by repeated homogenisation, in the form of A, C, and D. Homogenisations under different conditions of ionic strength, or after prolonged autolysis yield closely similar results: the ratios of A, C, and D are remarkably constant. Moreover ammonium sulfate precipitation does not affect these species. This raises the question of their relationship and significance. All three species are recognized by antibodies obtained from rabbit immured against the purified enzyme. We have also studied the solubilization of acetylcholinesterase by trypsin in electric tissue slices. This is very effective and directly yields species B. This species, which is homogeneous in sedimentation, but might contain a variety of slightly different protein molecules, can also be obtained by partial tryptic digestion of A, C, and D, The sedimentation coefficient of species B is very close to that of purified acetylcholinesterase and we have previously suggested that the two kinds of molecules may be similar. Even though this is probably correct, we have been able to detect a significant difference (0.8 S unit) in the sedimentation coefficients. [ABSTRACT FROM AUTHOR]

Under standard assay conditions, the replicative DNA polymerase partially purified from rat liver non-histone chromosomal proteins exhibited a marked preference for native DNA over heat-denatured DNA as the template. However, work reported in the present paper demonstrates that this template preference could be reversed by changing the enzyme to template ratio in the assay system. This change in template preference was observed when either the concentration of DNA polymerase or of DNA was varied. Furthermore, it is shown that this alteration in template specificity is not the direct result of the action of an alkaline endonuclease present in the DNA polymerase preparation. [ABSTRACT FROM AUTHOR]

The purpose of this study was to demonstrate the presence of exoantigens in the intestinal washes of mice infected with H. nana, to partially purify the antigen, and to show identity with heterologous antisera to H. nana soluble proteins. This paper describes the increase in specific activity to tapeworm exoantigens with increased purification both with serum obtained from infected mice and heterologous rabbit serum. [ABSTRACT FROM AUTHOR]

Both rRNA and protein components of Escherichia coli ribosomes have been specifically labelled without any important loss of activity for polyphenylalanine synthesis in the cell-free system. Three adenylic residues per 70-S ribosome were labelled by an anthracenyl derivative and the ribosomal proteins by dansylation of four amino acid residues per 70-S particle. The association between the two complementary subparticles, the formation of the binary and ternary complexes in the presence of mRNA and tRNA were investigated using the concomitant measuring of fluoroscence intensity and polarisation of the two kinds of labels. The formation of these complexes involves the rRNA and the ribosomal protein components of the 30-S and 50-S subparticles directly and/or indirectly. The mobility of the messenger bound to the 70-S ribosome in the presence of tRNA is indicated by use of a polyadenylic acid labelled with the same marker ss that for rRNA. Reversible conformational changes are observed during acidic-alkaline titrations and melting curves of fluorescent ribosomal particles. The irreversible denaturation occurs at the same pH and melting temperature for the rRNA and the ribosomal components: The results are interpreted in terms of highly specific interactions between the rRNA and the proteins, slight modification in the strength and/or nature of these interactions leading to a conformational change of the whole ribosomal particle. [ABSTRACT FROM AUTHOR]

A theoretical analysis of linear enzymatic chains is presented. By linear approximation simple analytical solutions can be obtained for the metabolite concentrations and thc flux through the chain for steady-state conditions. The equations are greatly simplified if the common kinetic constants are expressed as functions of two parameters, i.e. the thermodynamic equilibrium constant and thc "characteristic time". Three cardinal terms are proposed for the quantitative description of enzyme systems. The first two are thc control strength and the control matrix; these indicate the dependence of the flux and the metabolite concentrations, respectively, on the kinetic properties of a given enzyme. The third is the effector strength, which defines the dependence of the velocity of an enzyme on the concentration of an effector; it expresses the importance of an effector. By linear approximation simple analytical expressions were derived for the control strength, the control matrix and the mass-action ratios. The effector strength was calculated for two cases: for a competitive inhibitor and for allosteric effectors according to the Monod (1965) model. The influence of an effector on the concentrations of the metabolites was considered. [ABSTRACT FROM AUTHOR]

Describes reaction of glutamate dehydrogenase with glyoxal and NaB[sup 3]H[sub 4] and the labelled protein digested with trypsin. Isolation and identification of radio peptides in the primary structure of the enzyme; Small amounts of radioactivity contained in many peptides; Unspecific reactions with glyoxal; Identification of lysine-27 as the residue reacting with glyoxal; Conclusion that lysine residues.

If an aqueous solution of [32P]phosphate is shaken with a chloroform-extract of rat liver mitochondria, the label is bound specifically by a number of chloroform-soluble proteins. Several chloroform-soluble proteins contain free SH-groups, as indicated by the binding of [14C]ethacrynate, a specific reagent for SH-groups. One fraction of chloroform-soluble proteins binds phosphate in high amounts, and this binding of phosphate is specifically inhibited by SH-reagents. Among various labeled anions (phosphate, malate, citrate, glutamate and ADP) only phosphate was shown to be bound at a significant amount by a chloroform-extract of rat liver mitochondria. [ABSTRACT FROM AUTHOR]

Bence-Jones protein DEL was isolated from the urine of a patient with multiple myeloma by ammonium sulfate precipitation. Ion-exchange chromatography provided no further purification of the protein; the ammonium sulfate precipitate consisted of only one protein moiety as tested by polyacrylamide electrophoresis. Protein DEL contains 213 amino acids and has a molecular weight of 22500. Eighteen peptides have been isolated by ion-exchange chromatography after tryptic digestion of the completely reduced and aminoethylated protein. Sequence studies were performed mainly on these tryptic peptides. In addition, 14 chymotryptic pepfides were isolated and characterized to obtain overlapping peptides for the whole V-region and for some tryptic peptides of the C-region. Protein DEL is related to subgroups III and IV of the γ-chains as indicated by a deletion of three amino acids after position 27, a common pattern of these two subgroups. Furthermore, position one is deleted in protein DEL as in the other proteins of subgroups IH and IV but in contrast to subgroups I and II of the γ-chains. However, marked differences exist between protein DEL and the proteins of subgroups IH and IV. a) The deletion of two amino acids in positions 95 and 96, characteristic of subgroup IV, was not found in protein DEL. b) 19 of the 27 linked exchanges specific for subgroup IV are substituted in protein DEL. Although the insertion of two amino acids after position 94 is the same as in subgroup III, a high exchange rate was observed for proteins DEL and Sh. Therefore it is concluded that protein DEL does not belong to either subgroups III or IV, but is the first example of a new subgroup of the γ-chains. [ABSTRACT FROM AUTHOR]

The lipid-containing bacteriophage PM2 has four distinct structural proteins, as shown by polyacrylamide gel electrophoresis in the presence of sodium dodecylsulfate or electrophoresis on cellulose acetate strips in the presence of 6-8 M urea. The molecular weights of these four polypeptides determined in several polyacrylamide gel systems are: I = 43000, II = 26000-27000, III = 12500, IV = 4700. The isoelectric points of the four viral proteins were determined on disrupted virus particles by electrophoresis on cellulose acetate strips in the presence of 6 M urea at various pH values. The mobilities were extrapolated to zero mobility, a method preferable to isoelectric focusing where the denatured viral proteins aggregate and precipitate near the isoelectric point. The method is well suited for the determination of the isoelectric point of proteins in thc native or only partially denatured state. Whereas proteins I, III and IV have isoelectric points slightly under neutrality (pH 6.2, 5.8 and 5.5, respcctively), thc isoelectric point of protein II is around 12.3. Calcium ions are tightly bound to protein II. After removal of the calcium ions in the presence of 6 M guanidine hydrochloride and EDTA, the pi of protein II is 9. The isoelectric point of thc intact virus, determined on cellulose strips, is around 7.3. Protein I, the spike protein, is the only structural polypeptide which is soluble in aqueous solutions around pH 7. All of the proteins are soluble in 6-8 M urea or 6 M guanidine hydrochloride at pH 7-8.5. Proteins III and IV. the nucleocapsid core proteins, have the solubility properties of proteolipids or highly lipophilic polypeptides as shown by their solubility in nonionic detergents and by their distribution in a Bligh and Dyer fractionation. Neither glycolipids nor glycoproteins are present in the virus. The distribution of phospholipids has been determined by chemical modification of the outer lamella or outer and inner lamellae of the bacteriophage lipid bilayer. The viral lipid bilayer is asymmetric; most of the phosphatidylglycerol residues form the outer lipid layer, most of the phosphatidylethanolamine residues the inner lipid layer. A complete model of the virus, including the assembly process, is discussed at the end of this report. [ABSTRACT FROM AUTHOR]

By using the principles of structural kinetics previously formulated, the effects of subunit interactions and conformation changes on transient rate of catalysis have been investigated for one-substrate dimeric enzymes. The analytical solutions of transient rate equations and the expression of the induction time, T, have been obtained for the following models of protomer interactions: simple sequential, partially-concerted, fully-concerted, and exclusive allosteric. The progress curve of the reaction during the pre steady-state phase, as well as the curve expressing the variation of τ-1 against substrate concentration. [S]. have been simulated by computer analysis. When the protomers do not exhibit any interaction in the simple sequential mechanism, the plot τ-1 versus [S] is a straight line and the induction time is always positive. If subunit interaction occurs but does not change during substrate binding, the plot of τ-1 against [S] is still linear but the length of the induction time depends on the value of the interaction coefficient. If this value is much lower than one, the enzyme, although Michaelian, behaves as "hysteretic" when rapidly mixed with its substrate. In the same way, the exclusive allosteric model also predicts positive τ values, but the plot of τ-1 against [S] is a curve reaching a plateau for high concentrations of the substrate. The sequential models (simple, partially-concerted, fully-concerted) can give rise to either positive or negative induction time. Moreover, the asymptote of the curve τ-1 against [S] is oblique. It is thus possible, at least in theory, from pre-steady-state kinetics alone, to rule out either the exclusive allosteric or the sequential models. The above theoretical developments have been applied to the early kinetics of L-phenylalanine ammonia-lyase reaction. The induction time, that can be calculated from the progress curve, is negative for a large range of substrate concentrations. This result allows one to rule out. for that enzyme, the allosteric transition as a possible explanation of cooperativity. Sequential binding of substrate and subunit interactions can thus generate a burst, that is a transient activation of the reaction in the absence of any activator. It is tempting to assume this transient activation to be of regulatory significance. [ABSTRACT FROM AUTHOR]

The protein part of phospholipase A2 from the venom of the common European honey-bee consists of a single chain of 128 amino acid residues [l], eight of which are half-cystine. The absence of free sulphydryl groups indicates that the enzyme contains four disulphide bridges. Digestion of the native enzyme with pepsin resulted in formation of a fragment containing all four disulphide bridges. Further digestion of this fragment with trypsin allowed the isolation of two singly cross-linked peptides, one containing half-cystine residues 37 and 107, and the other containing residues 59 and 99. A fragment containing the remaining two disulphide bridges was digested with dilute sulphuric acid and a peptide was isolated from the digest in which half-cystine residues 9 and 30 were linked. The remaining disulphide bridge is between residues 31 and 89. [ABSTRACT FROM AUTHOR]

Microtubule protein isolated from muscles of 11-day-old chick embryos migrates in gel electrophoresis with sodium dodecylsulphate-5% polyacrylamide as two closely associated bands of molecular weight 55000, which account for more than 90%, total protein. Incubation of the microtubular protein with [γ-32P]ATP and Mg2+ results in a rapid incorporation of radioactivity into 5% trichloracetic acid precipitable fraction, without addition of any exogenous protein phosphokinase. The radioactivity can be solubilized by proteolytic enzymes and by alkali, and it migrates together with the faster moving band on gel electrophoresis. Elution of the tubulin band followed by acid hydrolysis gives rise to [32P]phosphorylserine. The protein phosphokinase activity associated to the microtubules is not stimulated by cyclic AMP or cyclic GMP and it can act on exogenous substrates, like casein, histone and phosphovitin. It emerges upon filtration through Bio-gel P-300 at a position of molecular weight 54000, separated from the bulk of the 32P radioactivity, which coincides with [³H]colchicines binding (molecular weight 120000). Phosphorylation by ATP (Km = 8 μM) requires Mg2+ or Mn2+. GTP can replace ATP in the phosphorylation reaction. Casein phosphorylation by ATP or GTP is affected only slightly by NaCl and vinblastine, but that of tubulin is affected to different extents, depending on the nucleoside triphosphate used. The microtubular protein isolated: (a) HeLa cells cultured in the presence of 32Pi; (b)muscle and brain slices of chick embryos incubated with 32Pi, and (c) muscles and brains chick embryos injected with 32Pi, is labeled in all instances with 32P. The radioactivity migrates on gel electrophoresis like tubulin and gives rise upon elution and acid hydrolysis to [32P]phosphoserine. The results in vitro as well as those obtained in intact cells are discussed in connection with the possible role of phosphorylation as a control mechanism of microtubular function. [ABSTRACT FROM AUTHOR]

The water proton-relaxation times, T1 and T2have been measured in solutions of Mn(II) and ATP in the presence and absence of rabbit muscle phosphofructokinase over a wide range of temperatures and nuclear frequencies, using pulsed nuclear magnetic resonance techniques. The equilibrium between the enzyme and the Mn · ATP complex has also been studied as a function of temperature, and the relaxation rates in the bound complex determined. An analysis of the relaxation rates in both free and enzyme-bound Mn · ATP sites according to established theories of paramagnetic relaxation has been carried out by means of graphical and computing methods, and yielded estimates of the Mn(II) water co-ordination number (q) and the relevant correlation times their frequency and temperature dependence. Relaxation in the ternary enzyme complex is dipolar in nature and the correlation time (Τ) is dominated by the water residence time (ΤM) or the Mn electron spin relaxation time (Τs) according to frequency. The values obtained for both Τc and &Taus are longer than earlier estimates. In the binary Mn · ATP complex the dipolar interactions are dominated by rotation (ΤR) but in addition there is a large scalar interaction governed by both ΤM and Τs. The significance of the parameters in the structure if the ternary enzyme complex is discussed, together with the implications of the revised parameters &Tauc and &Taus for earlier mapping studies of the Mn · ATP sites and the spin-labelled enzyme. The limitations of the analysis have been stressed throughout. [ABSTRACT FROM AUTHOR]

An IgG1 type of protein with the genetic marker combination Gm(f), non a, and (x) has been described. The evidence from studies on isolated IgG1 Fc fragments showed that the IgG1 protein was of normal size. No Gm markers other than the three mentioned were found. Thus, there was no evidence for deletions or duplications giving rise to the unusual IgG1 protein. In contrast, the origin of the unusual genetic marker combination appears to be a rare IgG1 gene Gmf non a, x, probably due to an intragenic recombination at the IgG1 cistron. [ABSTRACT FROM AUTHOR]

The mycelium of Neurospora crassa was cultivated in a minimal liquid medium in surface culture. The moist mycelium was lyophilized, powdered, and eluted using 0,14 M sodium chloride solution for extracting the proteins. The enrichment of these proteins was carried out by means of ultrafiltration (vacuum and pressure filtration). The extracted proteins of N. crassa were characterized by paper-, agar gel- and immuno­electrophoresis. The antisera were obtained by immunising rabbits for 21 weeks. By means of agar gel electrophoresis 5 zones of proteins were separated in N. crassa 3a6A; by means of immunoelectrophoresis 17 bands resulted from the same protein mixture. The electrophoretic mobilities of the precipitation arcs were calculated. The immunoelectrophoretic patterns of N. crassa E 5256 obtained by N. crassa 3a6A antiserum nearly agreed with the bands of N. crassa 3a6A antigen. However there were no corresponding results in the patterns obtained from N. crassa 46001-1-1a and N. crassa 6994a with the same antiserum. It may be assumed that these differences depend on the different genetic enzyme patterns of the wild and mutant strains; they are also responsible for the differences in the rates of synthesis depending on the duration of cultivation. [ABSTRACT FROM AUTHOR]

We have studied the ribonucleosidediphosphate reductase of a deoxyuridine-requiring mutant LD195 of Escherichia coli K. This enzyme was purified 50 fold from the mutant and a control strain. In all steps of the purification the mutant strain yielded normal activity of the Bi subunit of the enzyme but approximately 10 % of the wild-type activity of the B2 subunit The activity is similarly reduced for all three substrates tested CDP, UDP, and GDP. The mutation appears to affect the physical structure of the B2 subunit, since addition of high concentrations of sodium acetate can restore enzymatic activity to the partially purified B2 subunit from the mutant strain. In contrast, the same concentrations strongly inhibit the wild- type B2 subunit. Although the mutant has a requirement of deoxyuridine at 42 °C but not at 30 °C (as shown in an accompanying paper), mutant protein B2 is not more thermo-labile than wild-type protein B2 This requirement therefore probably reflects an increased demand of deoxyribonucleotides at higher temperatures. Hydroxyurea inhibits mutant and wild-type ribonucleosidediphosphate reductase to the same extent in vitro. In spite of this, hydroxyurea inhibits growth of the mutant strain at a 20 fold lower concentration than that required for comparable inhibition of growth of the parent. This is explained by the greatly decreased protein B2 activity of the mutant. [ABSTRACT FROM AUTHOR]

For the elucidation of the amino-acid sequence of the carboxyl-terminal region of soybean trypsin inhibitor (Kunitz), fragments C and D were digested with trypsin, and the resulting peptides were separated by ion-exchange chromatography on Dowex 50X2 or by gel filtration on Bio-Gel P-4. Further fractionation and purification of the peptides were performed by ion-exchange chromatography on Dowex 1X2, by gel filtration on Bio-Gel P-2 or by high-voltage paper electrophoresis at pH 1.9 and 3.6. Three peptides were obtained in pure form from fragment C and ten peptides from fragment D, and their amino-acid sequences were determined by the direct Edman method and by carboxy- peptidase digestion technique. Overlapping peptides necessary for the alignment of the tryptic peptides from fragment D were obtained from a chymotryptic hydrolysate of fragment D. Nine main peptides and rune minor peptides were obtained. The amino acid composition and the partial amino-acid sequence of the 18 chymotryptic peptides of fragment D made it possible to establish the amino-acid sequence of the carboxyl-terminal region of the inhibitor. The complete amino-acid sequence of soybean trypsin inhibitor (Kunitz) deduced here was compared with that of Bowman-Birk inhibitor, another well-known soybean proteinase inhibitor. [ABSTRACT FROM AUTHOR]

1. Tryptic hydrolysates of denaturated glutamic-aspartic transaminase fractionated on a Sephadex G-25 column, gave an elution diagram containing six main fractions. When peptide maps were developed from the transaminase digest 37 spots were detected on the paper sheet. 2. It was demonstrated that the transaminase fractions (groups of peptides) as well as some of the individual peptides eluted from the map spots, possessed immunological activity. This was proved by theft capacity to interact with rabbit pig heart antienzyme and rabbit antiserum against the pig-heart whole tryptic transaminase hydrolysate as well as to inhibit the homologous transaminase-antitransaminase reaction. Higher immunological reactivity was found among peptides moving faster in electrophoresis and chromatography. 3. The catalytic activity of rabbit transaminases (heart, liver, skeletal muscles), was inhibited to a substantial degree by the rabbit anti-pig heart transaminase. The above enzymes however. as was otherwise expected, gave negative precipitin reactions with antitransaminase. A comparative study of the reactivity between transaminases from pig, ox and rabbit and rabbit antitransaminases against pig and ox heart enzymes as well as against pig-heart whole tryptic transaminase hydrolysate is presented here. [ABSTRACT FROM AUTHOR]

The intra-cellular localization of the herbicide N,N-dimethyl-2,2-diphenylacetamide (diphenamid) was examined in 10 mm root tips of corn seedlings (Zea mays L. cv. Shawnee). Experiments are described which culminate in the observation. that a significant, measurable effect on root growth occurs within 12 hours after treatment with diphenamid. Corn seedlings were then treated with 14-C-diphenamid for 12 hours and the 10 mm root tips excised and homogenized. By use of differential centrifugation and gel filtration, the root homogenate was separated into fractions as follows; cell wall, mitochondria, microsomal, protein and eluate. The highest concentration of the herbicide was found in the root tips. Furthermore, most of the radioactivity was found in the eluate. Results are discussed as to localization of diphenamid in the microsomal and protein fraction and possible mode of action. [ABSTRACT FROM AUTHOR]

δ-Aminolevulinic acid supplied to dark grown isolated leaves of wheat causes an accumulation of protochlorophyllide which is only partly transformed to chlorophyllide α in continuous light. At the same time a considerable photodestruction of both pigments takes place. By a suitable combination of short light flashes and dark periods it is possible, however, to obtain at least double the amount of the protochlorophyllide transformed without photodestruction. The transformation is shown to be dependent on the dark interval between the light flashes. Possible connections with the formation of the protein part of the protochlorophyllide holochrome are discussed. [ABSTRACT FROM AUTHOR]

The theory that Skeletonema cells adapt to lower temperatures by increasing their enzyme concentration, is supported by various facts. While the rates of photo- synthesis are identical in cells adapted to different temperatures (7-20°C) the growth rate decreases with decreasing temperature and the production of organic matter increases with decreasing temperature. Further, the concentration of protein per cell and the height of the cells increase with decreasing temperature. [ABSTRACT FROM AUTHOR]