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SummaryEthanolamine isolated following administration of C14-carboxyl-labeled glycine contained no radioactivity. This indicates that glycine is not directly reduced to ethanolamine in the body and that this occurs through the intermediate formation of serine.

The phosphatidylmethyltransferase enzyme system of rat liver microsomes has been dispersed by treatment with deoxycholate and sonic oscillation. With the dispersed preparation, complete removal of endogenous phospholipid substrates could be achieved. The latter showed an absolute dependency on added N -monomethyl aminoethanol or N,N -dimethylaminoethanol phosphatides for methylation to lecithin. Kinetic study of the methylation reaction indicated that a single enzyme is involved which catalyzes the stepwise methylation of N -methylaminoethanol phosphatide to lecithin. Tests were made of the suggestion that phosphatidyl serine might be methylated prior to decarboxylation and, in this manner, might yield the first observed substrate, the monomethylethanolamine phosphatide. It was demonstrated that this reaction does not occur. The only decarboxylation product detected was ethanolamine phosphatide.

1. 1. Liver arginase (E.C. 3.5.3.1) of various mammalian species (rat, mouse, dog, rabbit, pork, monkey) were partly purified and their isoelectric properties determined by carboxymethyl cellulose column chromatorgraphy and isoelectric focusing. 2. 2. The ureotelic arginase can be divided into mainly two groups; (i) basic and (ii) slightly acidic or neutral proteins. 3. 3. The two groups of arginases showed marked differences in the binding of Mn2+. 4. 4. Only beef liver arginase could be activated by Co2+ and Ni2+, all other mammalian arginases were inhibited by these metal ions. 5. 5. The molecular weights were found to range from 120,000–160,000 daltons. 6. 6. High Michaelis constanta (6–20 mM) were obtained for all arginases studied. 7. 7. Similarities were also found in the pH optima (pH 9·3–10·5) as well as the optimal Mn2+ concentration (40 mM) required to obtain maximal catalytic activity.

An enzymic microassay for arginase was developed which is accurate and rapid and can be followed continuously on a recording spectrophotometer. The reaction of arginase is coupled with l -ornithine aminotransferase and the resulting glutamate determined with glutamic dehydrogenase and simultaneous reduction of NAD. Optimal reaction conditions were developed and the results of the colorimetric method compared with the isonitrosopropiophenone assay.

Publisher Summary This chapter discusses the synthesis and transformations of folic coenzymes II, the cyclohydrolase (5,10-methenyl to 10-formyl). This enzyme was observed in lyophilized cells of Clostridium cylindrosporum and a method for its estimation was reported. dl-5,10-Methenyltetrahydrofolic acid (anhydroleucovorin) was prepared by dissolving approximately 15 μmoles of calcium leucovorin in 10 ml of 0.1 N HC1 containing 600 μmoles of mercaptoethanol. This was incubated in a vacuum in the dark at 25° for 24 hours and then stored in a vacuum at 0°. The assay was performed by measuring the decrease in absorption at 355 mμ in an incubation mixture containing 0.2 ml of 1 M potassium maleate buffer, pH 6.5, 280 μmoles of mercaptoethanol, enzyme, and 0.075 μmole of dl-5,10-methenyltetrahydrofolic acid in a total volume of 1 ml. In neutral and alkaline solutions the reaction catalyzed by the enzyme proceeds spontaneously. This nonenzymatic hydrolysis is markedly affected by the nature and concentration of the buffers used. It is found that phosphate and imidazole accelerate the reaction at pH 6.5, whereas the rate is relatively slow with triethanolamine sulfate and potassium maleate.

A mica window Geiger counter tube is described which combines the speed of a metal walled tube with a sensitivity to soft radiations comparable to that of the screen walled tubes. It consists of a NO2 treated metal cylinder covered at one end by a thin sheet of mica (0.02 mm) and at the other end by a glass bell with a central capillary. Through this capillary is sealed a piece of 8‐mil tungsten wire with a drop of glass fused over the end. The tube is operated at a pressure of 10 cm of Hg with a mixture of 10 percent ethanol and 90 percent argon.

Studies of Urocanic Acid: Intermediate Products in the Enzymatic Degradation of Urocanic Acid

SummaryN-substituted amino acid can be separated by paper chromatographic method. Also, N-substitution leads to the extinction of fluorescence of amino acids.

SummaryThe influence of the thyroid on the acetylation of sulfanilamide was studied Hyperthyroidism and thyroidectomy cdused a decrease in the amount of sulfanilamide acetj lated : thiouracil treatment led to an increase.

SummaryThe diffusible substance present in blood acted as a thromboplastin in accelerating coagulation. The prolonged dialysis required to demonstrate this action produced destructive changes in the plasma factors involved in coagulation.

Cases of rickets uncomplicated by renal disease which did not respond to the antirachitic treatment with ordinary doses of vitamin D have been reported by a number of investigators. 1 Chemical balance studies of the bone salt metabolism have been carried out in a number of these cases. 1f, g The changes in calcium and phosphorus metabolism have been reported to be not quite typical of ordinary infantile rickets but not at all like those of primary hyperparathyroidism. The urinary excretion of calcium has been reported to be above the level usually observed in active rickets. There is chemical evidence of a secondary hyperplasia of the parathyroids in this condition. Since hyperplasia of the parathyroids has been shown to be associated with rickets in experimental animals, this feature does not appear to be a unique characteristic of resistant rickets. The use of induced radioactive isotopes of the biologically important mineral

The reduction of calcium in the blood in infantile tetany and in tetany due to parathyroid deficiency has been well recognized since the classic work of McCallum and Voegtlin. 1 On the other hand, no significant alteration in the total amount of calcium in the serum has been found in tetany induced by hyperventilation or by an overdosage of bicarbonate. 2 The differences in the analytic observations of the chemical composition of the blood in tetany of diverse origin 3 led Grant and Goldman to conclude: "Tetany occurs under so many circumstances that it probably cannot be attributed to a single etiological factor." This, however, has not deterred many from attempting to establish a common disturbing factor as the cause of all forms of tetany. Two hypotheses have been proposed with respect to the etiologic factors responsible for tetany: 1. All forms of tetany are due to an alkaline shift in the acid-base

Investigations into the state of the blood calcium in diseases accompanied by jaundice have been carried out mainly in three directions: the direct examination of the total calcium content of the whole blood, serum or plasma of jaundiced patients and experimental animals; the determination of the toxicity of bile and bile salts as modified by the action of calcium salts, and the injection of these into the blood stream of experimental animals; and by therapy with calcium salts, cod liver oil and ultraviolet radiation, and by the action of extract of parathyroid hormone in experimental animals and in man. The most consistently and most widely quoted works are those of King and Stewart,1Lee and Vincent,2Vines,3Groves and Vines,4Kirk and King5and Walters and Bowler.6It is largely on the basis of these investigations, in which the three methods of approach mentioned were employed, that the current opinion

Experimental work has been carried out to determine according to the well known method of Hittorf the transport numbers of caesium, sodium and potassium caseinates. Constancy of pH was maintained throughout the experiment by the aid of a non-polarizable cathode. Casein was deposited on a platinum wire which constituted the anode. The experimental results indicate that in the solutions which were employed the current is carried by the caesium, sodium or the potassium as cations and the casein as anion. These results are not in harmony with the hypothesis which postulates that the protein ionizes to give two complex protein ions rather than an inorganic ion and a protein ion. The experimental data will be published in detail in the near future.

Several workers have suggested that abnormalities in calcium metabolism may be significant in the genesis and development of neoplasms in man and in other animals. Thus Clowes and Frisbie1found calcium to be markedly low and potassium high in actively growing malignant tissue. Goldzieher2and Theis and Benedict3reported low values for the total serum calcium in patients afflicted with carcinoma and other malignant tumors. Reymond, Sendrail and Lassalle4and Sendrail5claimed that a lowering of the serum calcium occurred in the precancerous phase of animals with experimentally induced neoplasms. Finally, McDonald6went so far as to state that cancer is a disease associated with a lessened amount of total and ionized calcium in the blood. These observations led us to investigate the calcium fractions, the proteins and the inorganic phosphate of the blood serum in fifteen patients suffering from malignant diseases. Recent work in the field of calcium metabolism7

The calcium metabolism in allergic diseases has recently been the subject of investigation by a number of workers. The principal method of approach has been through the study of the total calcium content of the serum by methods similar to the Kramer and Tisdall method1for the analysis of the blood for calcium. Such studies have been based mostly on the assumption of a deficiency of calcium in the blood and are supported principally by the indirect evidence that symptomatic relief has been obtained in certain instances through therapy with calcium salts. The mass of the analytic data, however, critically reviewed, indicates that the total serum calcium values lie within the range of normal variation.2For a discussion of the normal values, the reader is referred to the recent work of Criep and McElroy,2who also reviewed the present status of calcium therapy in atopy. As a part of the

The use of agents capable of influencing the calcium content of the blood in the treatment of many pathologic conditions has become a widespread medical procedure. 1 When there is any rational basis at all, the purpose of these reagents is to counteract a deficiency, presumed or real, in blood or tissue calcium. In some instances, it is true, the treatment is given, not for the direct effect on calcium, but for secondary effects such as to decrease hemorrhagic tendencies or to relieve edema. A sound rational basis for calcium therapy depends on an extensive knowledge of the influence of the agents commonly employed on the biochemistry of the body calcium and other bodily constituents that are interrelated with the calcium. Since it is naturally difficult to study the whole of the body calcium, attention has been given mainly to the effect on the blood calcium. Many studies have been

SEVERAL lines of evidence serve to establish glutamic-γ-semialdehyde as the key intermediate in the pathway of the biosynthesis of proline from either glutamic acid or ornithine1,2. Since glutamic-γ-semialdehyde spontaneously cyclizes nearly completely to Δ1-pyrroline-5-carboxylic acid2, hydrogenation of the latter becomes a key reaction in the biogenesis of proline.