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Lectins from the surface of Azospirillum brasilense Sp7 and Azospirillumn brasilense Sp7.2.3 (a mutant with impaired lectin activity) were shown to induce a stabilizing effect on the activity of almond beta-glucosidase under conditions of thermoinactivation and proteolytic enzyme treatment. Differences were revealed in the influence of lectins with various antigenic properties. Our results indicate that the effects of lectins on the catalytic activity of the enzyme are mainly associated with conformational changes in lectin molecules during mutagenesis, but not with carbohydrate specificity (general property). These data should be taken into account in evaluating the role of lectins in the formation of nitrogen-fixing associations.

It was demonstrated that the presence of acid proteinases in the preparation isolated from Aspergillus awamori decreased the activity and stability of glucoamylase. Patterns of changes in the enzymatic activity and stability of glucoamylase at increased temperature and various pH values were studied over a long-term storage. A biospecific sorbent for removal of acid proteinases was synthesized, and glucoamylase preparations free of proteolytic activity were produced.

We demonstrated for the first time that alkylhydroxybenzenes (the d1 microbial autoregulatory factors involved in stress responses of cells) are capable of stabilizing enzymes in aqueous media and increasing their catalytic activity. The stabilizing effect of a chemical analogue of alkylhydroxybenzenes, C7-AHB, was established in in vitro studies with enzymes of microbial origin: a protease produced by Bacillus licheniformis, cellulase produced by Trichoderma viride, and alpha-amylase produced by Bacillus subtilis. This effect manifested itself in considerable extension of the temperature and pH ranges of the enzymatic activity. The modulation of the catalytic activities of the stabilized enzymes depended on the C7-AHB concentration and on the time of preincubation of the complexes obtained. We demonstrated that not only enzymes but also their polymeric substrates formed complexes with C7-AHB, and this also significantly influenced the efficiency of hydrolytic reactions. We also conducted comparative studies on the efficiency of hydrolytic reactions in systems in which the structure of enzymes and/or substrates was modified with C7-AHB.

In this paper was investigated stability of isoenzymes of lactatdehydrogenase (LDH) of leukocytes of peripheral blood of persons at the age of 20 years (n=10) and more than 65 years (n=8). Extraction of the leukocytes was conducted by centrifugation of human blood on a double gradient of density. Leukocytes were destroyed by hypotonic shock in combination with vibration. Separation of LDH isoenzymes from destroyed leukocytes was conducted by the method of native electrophores. The revealing of activity of LDH isoenzymes was conducted by the method of restoration of nitroblue tetrasolium. Isoenzymes stability was evaluated according to alteration of activity after the incubation of destroyed leukocytes with urea in various concentrations (1M, 2M and 3M). Was shown the presence of three isoenzymes of LDG (LDH-1, LDH-2, LDH-3) in human leukocytes. As the age-dependent alteration of activity of isoenzymes of lactatdehydrogenase in human leukocytes was shown. It can be caused by age-related changes of physico-chemical properties of leukocytes' membranes and/or isoenzymes stability. Stability of LDH-3 was decreased with the age. Observed decrease of LDH-3 stability can be caused by age-related modification of M-subunits of the studied isoenzymes.

Stability characteristics of the laccases of the basidiomycetes Coriolus hirsutus and Coriolus zonatus were measured comparatively at temperatures 25 and 40 degrees C in the presence of various effectors (proteins, salts, polyalcohols, polyacids, and polyelectrolytes). Stabilization effects of cations on the laccases from C. hirsutus and C. zonatus decreased in the descending series Cu2+ > Mg2+ > Ca2+ and Ca2+ > Mg2+ > Mn2+, respectively. Tween 20 caused insignificant stabilization of the two enzymes. The C. zonatus laccase was also insignificantly stabilized as a result of treatment with bovine serum albumin. The enzymatic activity of the laccase preparations from C. hirsutus and C. zonatus was conserved virtually completely after vacuum drying (84 and 93%, respectively). The most effective stabilizer of the C. hirsutus laccase was found to be dextran (17 kD). Dry preparations treated with this agent conserved up to 95% of the enzymatic activity. The most effective stabilizer of the C. zonatus was polyacrylic acid (102% of the initial activity).

Effects of pH, enzyme concentration, and various supplements on the catalytic activity, temperature stability, and secondary structure of horseradish peroxidase (HRP) were studied in diluted aqueous solutions. In 5.0 mM citrate-phosphate buffer (pH 4.2) at 55 degrees C and infinite dilution, HRP was inactivated with a rate constant of 2.86 x 10(-3) s-1. CaCl2, BSA, and glycerol caused protective effects, whereas KCl, LiCl, maltose, PEG-6000 (at a concentration above 3%), Triton X-100, ethanol, and Kathon CG had an opposite effect and altered the secondary structure of HRP. Two HRP-stabilizing media: the "glycerol-based" one containing 10% ethanol and 20% glycerol, or the "protein-based" one containing 0.1% Kathon CG and 0.2 g/l of BSA in 50.0 mM Tris-HCl buffer (pH 7.2) supplemented with 50 mM CaCl2 were developed, and the stability of HRP (0.36 nM) and its immunoglobulin, cortisol, and progesterone conjugates were compared in these two media. The protein-based medium displayed a greater stabilizing effect particularly on HRP-steroid conjugates.

Acute and chronic experiments in dogs revealed participation of the salivary glands in ensuring a relative constancy of the blood enzyme activity. The saliva hydrolases reflected the spectrum of blood plasma and its disturbance and extend the possibilities of the sialoenzymodiagnosis.

Studies have been made on some of the properties of glycylleucyn- and leucylglycyne dipeptidases from the membrane and cytosol fractions of enterocytes of mice, rats and rabbits. Differences in cellular distribution of these enzymes in the species investigated were found. These enzymes also differ in their thermostability and the reaction to the effect of an inhibitor, 1,10-phenantrolyne. Presumably, these peptidases are presented by different enzymes which are subjected to separate genetic control.

The nonselective beta-blocker propranolol and the selective beta 1-adrenoblocker flusoxolol were tested for their effects on the activities of acid phosphatase, acid DNAase, cathepsin D, beta-glucosidase and beta-galactosidase in intact rat ventricular myocardial homogenates. The two drugs were found to have the most noticeable effect on the activity of three enzymes under study: acid phosphatase, beta-glucosidase and beta-galactosidase. They were able to stabilize lysosomal membranes during long-term homogenate preincubation at 37 degrees S. It is suggested that the mechanism of action of the drugs on intact rat ventricular myocardial lysosomes under the conditions of the study involves the binding of both propranolol and flusoxolol to beta-adrenoceptors on the lysosomes.

Regional localization of creatine phosphokinase BB was studied in postmortem human brain and its stability was shown. The content of CPK BB in different brain structures was unequal: from 0.5 mcg/mg of protein in the occipital lobe and tuber cinereum to 4.5 mcg/mg in the frontal lobe. In the regional localization of CPK BB in the postmortem brain of schizophrenia patients, some changes in isoenzyme content were found as compared to the control group. The reduction of CPK BB concentration at schizophrenia was found in the frontal lobe (45%, P less than 0.001) and s. nigra (70%, P less than 0.001); the concentration was higher in the thalamus and occipital lobe (15%, P less than 0.001), as well as in the parietal lobe, cingulate gyrus, tuber cinereum, cerebellum cortex, inferior olive--50-80%, P less than 0.001.

Aldolase turnover in rat hepatic cell culture and the influence of whole-body X-irradiation on the rates of synthesis and degradation of the enzyme and its "half-life" have been investigated. Aldolase biosynthesis in irradiated cells increases significantly as the rate of its degradation grows and the time of its functioning decreases.

Dextran-modified hyaluronidase was inhaled or intraperitoneally injected for 4 months to mice with silicosis. Stabilized hyaluronidase was shown to have a marked inhibitory effect on the development of lung fibrosis. Drug inhalation proved to be the most effective. An antifibrotic effect of dextran itself has been observed.