The effect of 4 groups of medicamentous agents, viz. neoruleptics, tricyclic antidepressants, somnifacients and antiepileptics - on the activity of the transport ATPase and p-nitrophenylphosphatase from the renal tubules of the guinea pig was studied. Used in high concentrations neuroleptics suppress almost completely the activity of the enzyme, but in small doses influence but little that of the p-nitrophenylphosphatase. The butyrophenone derivatives have a mild effect upon the activity of the p-nitrophenylphosphatase and in low concentrations they stimulate it. The effect of tricyclic antidepressants closely approaches the one produced by neuroleptics-phenothiazines. Lithium carbonate leaves the enzyme intact. Barbiturates and antiepileptic agents inhibit but feebly these enzymes.

In a period of lowest day activity of tyrosine aminotransferase, within 6-8 days after bilatheral adrenalectomy, the enzyme activity was decreased by about 20% as compared with an adequate control. At the same time, within a day and seven days after hypophisectomy, in rat liver tissue the enzyme activity was increased, approximately two-fold as compared with the normal state. Within four hrs after intraperitoneal administration into intact fasting rats at a dose of 2-2.5 g per 1 kg of body weight D-cycloserine and its dimer caused an induction of tyrosine aminotransferase by 75% and 180%, respectively. Induction of the enzyme by D-cycloserine and its dimer was inhibited by actinomycin D; the phenomenon was not observed in adrenalectomized rats. Within a day after hypophisectomy D-cycloserine did not cause the induction of tyrosine aminotransferase in rat liver tissue; to the contrary, the dimer of D-cycloserine caused induction of the enzyme, comparable to the ACTH effect, in liver tissue of hypophisectomized rats.

Experiments set up on mice demonstrated that galanthamine, hydrobromide, physostymine salicilate and iodomethylate produce a fall of the renal temperature, the hypothermal effect being proportional to the suppression of the cerebral cholinesterase. Anticholinergics benactyzine and atropine were largely capable of preventing hypothermia produced by the introduction of galathamine hydrobromide, the latter increasing the resistance of the animals to the action of high temperature.

Effect of beta-mercaptopropylamine on the activity of acid phosphatase was studied in liver, brain, spleen, thymus and blood of intact rats. The effect was observed within three days after the administration of beta-mercaptopropylamine. At the same time the weight of lymphoid organs (spleen and thymus) was distinctly altered. The alteration in the weight of the organs correlated with alteration in the enzymatic activity.

Administration of L-thyroxine into intact rats caused a distinct increase in the activity of hexokinase in liver tissue. In the isoenzyme spectrum of hexokinase the activity of hexokinase II was increased significantly. After repeated administration of insulin, liver tissue cells lost their capacity to respond to the hormone administration by induction of hexokinase. Administration of L-thyroxine into animals caused a distinct increase in the hexokinase activity in liver tissue. In isoenzyme spectrum of hexokinase under effect of L-thyroxine a significant increase in the hexokinase II activity was also observed.

Adrenaline myocarditis in rats was accompanied by a decrease in relative activity of pyruvate kinase from hyaloplasm of heart muscle, especially pronounced within 6-13 hrs after adrenaline administration. This phenomenon was probably due to an increase in content of protein in hyaloplasm, but not to an alteration in the enzyme activity. This conclusion was confirmed by studies of some properties of pyruvate kinase. Under these pathological conditions the Km of phosphoenol pyruvate was of the same order of magnitude as in normal state; 1-phenylalanine was characterized as an inhibitor of non-competitive type tomards phosphoenol pyruvate, and palmitate did not exhibit the inhibitory effect on pyruvate kinase as it was found in normal state. The effectiveness of the enzyme inhibition by L-phenylalanine, protection of the enzyme against this amino acid effect by L-alpha-alanine, L-serine and L-cysteine, and also the degree of activation of pyruvate kinase by the amino acids under adrenaline myocarditis were similar to those phenomena observed in normal state.

Five strains of A type Cl. perfringens of different titres of toxicity (BP6K, SR-12, 2836, 2910, 1) possessed a distinct activity of ornithine transcarbamylase. In cells the maximal activity of the enzyme was observed within 3-5 hrs of growth of the culture. The enzyme was partially purified and some of its physico-chemical properties were studied. Ornithine transcarbamylase was termostable. Monoiodine acetate, p-chloromercurybenzoate, semicarbazide, Hg-2+, Cu-2+ and Fe-3+ inhibited the enzymatic activity, but Mg-2+ and Ca-2+ activated the enzyme. Ornithine transcarbamylase was shown to be active in wide region of pH: from pH 6.0 to pH 9.0 and higher. Two peaks of the enzyme activity were observed: the first (a more distinct one) at pH 8.6-8.9 and the second, smaller,--at pH 6.5-6.7.

Deoxyadenosine, which was phosphorylated to dATP, inhibited DNA synthesis in malignant cells. However, on incubation of the substance in vitro with Zaidela ascites hepatoma cells the inhibitory effect was gradually decreased due to dephosphorylation of dATP and to deamination of deoxyadenosine to deoxyinosine. In order to prolong the inhibition of nucleic acids synthesis, N-6-methyl adenosine, which was recognized as an inhibitor of adenosine deaminase, was added to the cells. Optimal inhibition of DNA synthesis was observed in presence of deoxyadenosine and N-6-methyl adenosine at 1 with 10-minus 3 M concentration. Addition of N-6-methyl adenosine, after incubation with deoxyadenosine within 2 hrs, caused more prolonged inhibition of DNA and RNA synthesis than it was observed in presence of deoxyadenosine.

Creatine action on the activity of creatine kinase (ATP: creatine-phosphotransferase; EC 2.7.3.2) and the content of water-soluble proteins in the developing monolayer culture of chick myoblasts are studied. Creatine at concentrations of 1.9-10- minus 3-3.8-10- minus 3 M is shown to increase reliably the creatine kinase activity by 1,1--2,9 times and to reduct considerably the content of water-soluble proteins. Lower concentrations of creatine (3.8-10- minus 5 M) also increased the creatine kinase activity but did not change the contents of water-soluble proteins. The creatine effect was maximal at the period preceding the termination of tissue cells differentiation. In the course of the combined effect of both actinomycin D (50 mcg/plate) and creatine (3.8-10- minus 3 M) the creatine kinase activity was much higher than that in the presence of actinomycin D alone which considerably reduced the enzyme activity as well as the contents of water-soluble proteins.

Extracts of Thiocapsa roseopersicina cells show hydrogenase activity, measured by evolution of H2 from reduced methylviologene (MV) and by D2-H2O exchange reaction. According to these reactions the most part of hydrogenases is found to be in the soluble fraction. Hydrogenase activity measured in the exchange reaction is completely inhibited by p-chloromercurybenzoate (5-10- minus 3 M), iodacetate (1-10- minus 2 M) and 26% inhibited by KCN and o-phenanthroline (5-10- minus 3 M). Evolution of H2 from reduced MV was not inhibited by o-phenanthroline, KCN and iodacetate and was inhibited by 66% only with p-chloromercurybenzoate. Light and ATP stimulated hydrogenase activity of chromatophores did not affect on its activity in the soluble fraction. The results obtained show that there are certain differences in hydrogenase systems responsible for the exchange reaction and evolution of H2.

Analysis of E. coli W mutants defective in glucose transport suggests an existence of two enzyme systems which carry out the second step of phosphoenolpyruvate (PEP)-dependent glucose phosphorylation, thus controlling the glucose transport into E. coli cells. One system (PTS-glu-alpha) controls phosphorylation and transport of both glucose and alpha-methylglucoside, the other system (PTS-glu-beta) controls phosphorylation and transport of glucose only. PTS-glu-alpha system is damaged in the mutants studied, but PTS-glu-beta system is intact. On account of this fact the mutants do not uptake 14-C-alpha-methylglucoside and their extracts are practically incapable of its phosphorylation, phosphoenolpyruvate being used as phosphate donor. At the same time the mutants are capable of 14-C-glucose uptake and PEP-dependent 14-C-glucose phosphorylation. In one of the strain, having the intact PTS-glu-alpha system, the uptake of glucose and alpha-methylglucoside was stimulated by the addiction of glucose in the cultural medium. No such effect was observed in bacteria with the disturbed PTS-glu-alpha system and the intact PTS-glu-beta system. Probably, the PTS-glu-alpha system can be inducible, in contrast with the PTS-glu-beta system. The damage of the PTS-glu-alpha system results in resistance of bacteria to glucose-induced inhibition of the enzyme synthesis.

It was found that clinical strains of Ps. aeruginosa produced inducable beta-lactamase in the presence of penicillins, such as benzylpenicillin, ampicillin, carbenicillin. The amount of beta-lactamase depended on the strain and the inductor type and increased with the inductor concentration increase. Benzylpenicillin was the most active inductor of the enzyme synthesis by Ps. aeruginosa, strain 649. In concentrations of 5000 gamma/ml it provided at least 100 times higher amounts of beta-lactamase as compared to the initial level. The dynamics of induction of the enzyme synthesis by Ps. aeruginosa, strain 649 on addition of benzylpenicillin (5000 gamma/ml of the medium) at various stages of the culture growth was studied. Maximum accumulation of induced beta-lactamase was observed on addition of benzylpenicillin to the medium 2 hours after the culture inoculation. The induced enzyme was mainly found in the bacterialcells. The culture treatment with toluol increased the amounts of the determinable induced enzyme 4-26 times, 30 to 80 percent of the induced enzyme were liberated from the cells into the supernatant. Dependence of the level of the culture resistance to benzylpenicillin and ampicillin on the induction rate of beta-lactamase synthesis provided by the penicillins was found. No such dependence was observed with respect to the culture resistance to carbenicillin.

Kinetic and allosteric properties of beta-asparatatekinase from Micrococcus glutamicus-95 were studied. Coarse protein fraction, sedimented at 0.8 from saturated (NH4)2SO4, was used as an enzyme preparation. Curves of the dependency of the enzymatic reaction rate on substrate (L-aspartic acid and ATP) concentration were not found to be S-like. However, double reciprocal plotting of the data obtained revealed their deviation from the hyperbolic curve. The effect of amino acids (lysine, threonine, isoleucine, valine) on the activity of beta-aspartatekinase is studied. Lysine was shown to inhibit slightly beta-aspartatekinase, while threonine slightly activated it. Combined addition of both amino acids at a concentration of 1 mM resulted in the 50% inhibition. Isoleucine and valine activated beta-aspartatekinase and eliminated multivalent inhibitory effect of lysine and threonine. Interaction of isoleucine and lysine+threonine with beta-aspartatekinase was competitive with respect to L-aspartic acid and non-competitive in relation to ATP.

Some properties of acid alpha-glucosidase from pig spleen are studied. Changes in the enzyme activity with respect to polymeric and oligomeric substrates were shown to take place under effects of temperature, pH, concentration of metal ions, urea treatment, trehalose inhibition. Dextran and glycogen were used as polymeric substrates, and disaccharides with different types of bonds were taken as oligomeric substrates. The data obtained confirm the hypothesis on separate regions of binding polymers and oligomers with the enzyme molecule.

Due to orchidectomy, carried out two weeks before the experiment, in androgene-dependent rat tissues a hexokinase activity was found to be decreased several times. Within 24 hrs after administration of histamine into orchidectomized rats the hexokinase activity was increased by 96% in seminal follicles and by 160% in prostate. Incorporation of 3H-uridine into RNA of seminal follicles and prostate of castrated rat males was increased by 60% and 210%, respectively, within 3 hrs after the administration of histamine. The stimulating effects of histamine on RNA synthesis and the hexokinase activity were completely inhibited by actinomycin D. The data obtained suggest that histamine was one of mediators in the effect of testosterone on the tissues-targets.

Conformational transitions in membrane preparations of Na, K-dependent ATPase were studied by means of mono-radical and bi-radical hydrophobic spine probes. A decrease in micro-viscosity of non-polar membrane regions in Na, K-ATPase preparation was observed under the formation of phosphorylated N, K-ATPase intermediate in the presence of ATP and Na+ ions. K+-catalysed dephosphorylation of the intermediate resulted in opposite changes. Bi-radical probes of a certain chemical structure turned to be the most sensitive indicators of conformational changes in membranes of Na, K-ATPase preparation. Na+-, K+- and ATP-induced conformational transitions are blocked with suabaine, a specific inhibitor of Na, K-ATPase, with Ca2+ oligomycin and p-chloromercuric benzoate (PCMB). K+-dependent transitions are more sensitive to oligomycin and PCMB as compared with those induced by ATP and Na+. Possible mechanisms of conformational transitions in Na, K-dependent ATPase are discussed.

Based on fluorometric determination of a dipeptide histidil-leucine, which is splitted off from a synthetic substrate (Cbz-Phe-His-Leu) by carboxycathepsin (carboxydipeptidyl peptide hydrolase), a method was developed for estimation of the enzymatic activity in human blood serum. The method is characterized by simplicity and high sensitivity; Use of small amount of blood serum (about 0.03 ml) was possible. In normal human blood serum the carboxycathepsin activity varied from 7.5 to 18 nmoles of the dipeptide, liberated per mg of protein per hr.

The esters of aromatic acids with two electrophilic groups were found to inhibit mitochondrial ATP-synthetase like oligomycin. The substances without electrophilic sites or with one electrophilic groups have no the oligomycin-like effect on mitochondria. Aromatic acids with two alkylating groups are also inefficient.