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Biomedical subjects

V N Orekhovich

Publications and source records attributed to V N Orekhovich.

At least 37 records · Page 2Linked to original sources
PubMed1985

[Human erythrocyte prolyl endopeptidase II hydrolysing teprotid, an inhibitor of peptidyl peptidase from snake venom].

The paper is concerned with the action of 1200-fold purified prolylendopeptidase II (PE-E) from human erythrocytes and the action of highly purified prolyl-D-L-alanine peptidyl hydrolase (PE-A) from bovine adenohypophysis on teprotide (BPP9a, SQ 20881), a nonapeptide from venom of the snake Bothrops Jararaca--an inhibitor of peptidyl dipeptidase A (carboxycathepsin). Both the purified preparation PE-E and highly purified preparation PE-A split teprotide at the bonds Pro3-Arg4 and Pro5-Gln6. The Pro8-Pro9-OH bond was not split by the two enzymes. The comparative characteristics of the properties of PE-E and PE-A are presented and the possible physiological role of these enzymes is discussed.

Animals↗
PubMed1983

[Action of two thiol proteinases from the spleen which are active in neutral media on vasoactive peptides].

The action of two earlier isolated highly purified spleen thiol proteinases on angiotensins I and II, bradykinin and kallidin was investigated. It was demonstrated that proteinase I which is apparently cathepsin L from bovine spleen brings about rapid inactivation of angiotensin II with a splitting of the Tyr-Ile bond and a formation of two tetrapeptides. Proteinases I also split angiotensin I. Proteinase I partially inactivates bradykinin and kallidin by splitting the Gly4-Phe5 bond. The activity of proteinase I toward angiotensin II is about 50 times higher than that toward bradykinin. The corresponding values of Km and V are 7.5 X 10(-5) M and 10.0 mumole/min/mg. The possible role of proteinase I in angiotensin II inactivation under physiological conditions is discussed. Proteinase II converts kallidin to bradykinin by splitting off the N-terminal lysine. Proteinase II causes partial inactivation of bradykinin by splitting of the Gly4-Phe5 and Phe5-Ser6 bonds of this peptide. Proteinase II possesses both aminopeptidase and endopeptidase activities and is therefore cathepsin H from spleen. Proteinase II does not split either angiotensin I or angiotensin II.

Amino Acid Sequence↗
PubMed1983

[Prolylendopeptidase activity in various animal organs].

The paper is concerned with the distribution of prolylendopeptidase activity as measured by the hydrolysis of Z-Gly-Pro-pNA in extracts of various cattle tissues (hypophysis, liver, kidneys, heart, skeletal muscle, lungs, spleen, testicles, pancreas, thyroid, brain, small intestine, blood plasma). The highest specific activity was seen in the cerebral cortex, the lowest, in the spleen. The molecular weights of proteins with prolylendopeptidase activity in the extracts of the adenohypophysis, liver, kidneys, skeletal muscle and spleen were determined by gel filtration in an Ultrogel AcA 44 column, and the values of 57 000-66 000 dalton were obtained. Studies of the action of various inhibitors showed that complete inhibition of activity by PCMB (1 X 10(-3) M) was attained only in adenohypophyseal extracts, whereas in those of the spleen, skeletal muscle and liver, the inhibition reached 85%. The activity in the kidneys was inhibited by 65%.

Animals↗
PubMed1983

[Changes in dipeptidyl carboxypeptidase activity during hypertension and its complications].

Using the fluorimetric method, the activity of dipeptidyl-carboxypeptidase (DCP) was studied in 85 patients suffering from essential hypertension. It was ascertained that the DCP activity in the blood serum of such patients was significantly higher than in normal subjects. The highest activity of the enzyme was observed in cases where essential hypertension was aggravated by chronic heart failure or an acute impairment of the cerebral circulation. Inflammatory processes in hypertensive patients were associated with a considerable fall in the serum enzyme activity.

Adolescent↗
PubMed1982

Isolation of a cationic fragment of high molecular mass kininogen and effect of this fragment on human plasma kallikrein activity.

The effect of a cationic fragment of high molecular mass (HMM) kininogen on kallikrein activity and the autocatalytic process of prekallikrein-to-kallikrein conversion were studied. Prekallikrein and kallikrein were obtained by ion exchange and affinity chromatography; the purification of HMM kininogen was achieved using QAE- and DEAE-Sephadex, and separation of the cationic fragment was carried out by gel filtration. It was shown that the fragment of HMM kininogen (mol. mass. 7000, high lysine content) suppressed the activity of a labile form of kallikrein and prevented activation of prekallikrein. A model of the prekallikrein-kallikrein system is proposed. The model is based on the recently established fact of occurrence of two kallikreins and two kallikrein precursors. It involves formation from kininogen, besides kinins, of a kallikrein inhibitor.

Cations↗
PubMed1982

[Characteristics of two thiol proteinases from spleen active in neutral media].

Two SH-dependent proteinases (I and II) active in neutral media were isolated from bovine spleen and purified to apparent homogeneity. The histone-hydrolyzing activity of proteinase I was increased 3500-fold as compared to that of the original extract. Proteinase I hydrolyzed a variety of proteins (histones, azocasein, hemoglobin, collagen) but did not hydrolyze low molecular weight synthetic substrates, such as BAPA, BANA, BAEE, ATEE, Leu-beta-NA, Arg-beta-Na and Ala-beta-NA. The molecular weight of the enzyme as determined by SDS electrophoresis was found to be about 23,000. Isoelectrofocusing of the enzyme resulted in one major component with pI of 6.05 and in two minor components with pI of 6.2 and 6.4. Proteinase II hydrolyzed Leu-beta-NA, Arg-beta-NA and Ala-beta-NA but did not hydrolyze beta-naphthylamides of dicarboxylic acids and Gly-Phe-beta-Na. This proteinase split BANA and histone and very slowly split azocasein and collagen. Proteinase II was found to have a molecular weight of 30 000 and a pI of 6.8-6.9. Proteinase I inactivated fructose-1.6-diphosphate aldolase, partly inactivated glucose-6-phosphatase dehydrogenase and caused activation of phosphodiesterase of cyclic nucleotides. Proteinase II had no effect on the activity of the above enzymes. A comparison of proteinase I and II with enzymes described in literature demonstrated that the former was cathepsin L, while the latter was cathepsin H from spleen.

Animals↗
PubMed1982

[SH-dependent aminopeptidase from bovine kidney. Isolation, physico-chemical properties and substrate specificity].

The SH-dependent aminopeptidase was isolated from bovine kidney and purified 800-fold. The enzyme has a pH optimum of 7.0 and pI of 5.5 and is activated by dithiothreitol and inhibited by p-chloromercurybenzoate. The enzyme has a molecular weight of 56000 and is represented by four polypeptide chains with m. w. of 14000. Aminopeptidase hydrolyzes beta-naphthylamides of arginine, alanine, leucine and proline and peptides with free N-terminal neutral and basic amino acid residues having L-configuration as well as angiotensin III. The enzyme does not split proteins, angiotensins I and II, B-chains of insulin and peptides with a blocked N-terminal amino group and peptides with proline as a second amino acid from the NH2-end.

Aminopeptidases↗
PubMed1982

[Hydrolysis of synthetic peptides by group D cathepsins].

The effects of highly purified preparations of cathepsine D from human liver, spleen and some tumours on synthetic hexa- and heptapeptides were studied. The cathepsins were obtained by repeated chromatography on pepstatin-Sepharose with subsequent gel filtration through Sephadex G-100. The peptides tested were structural analogs of pepstatin, a natural inhibitor of carboxylic proteinases. In these analogs the amino acid statin essential for the inhibitory action was substituted for the residues of natural amino acids serine, threonine and glycine. It was shown that the peptides Ac-Val-Leu-Ser-Leu-Thr, Ac-Val-Val-Ser-Leu-Leu-Ser and Ac-Val-Val-Gly-Leu-Leu-Ser are appropriate substrates for cathepsins D. When leucine was substituted for isoleucine, the peptides were virtually resistant to the action of cathepsins D. The cathepsins from normal liver and spleen hydrolyzed only the peptide bonds formed by leucine. Cathepsins from malignant tumours exhibited a broader specificity in comparison with those from normal tissues, producing slight hydrolysis of other bonds.

Amino Acid Sequence↗
PubMed1981

[Glutamin(asparagin)ase from Pseudomonas aurantiaca BKMB-548].

A method for isolation of glutamin (asparagin) ase from Pseudomonas aurantiaca BKMB-548 has been developed. The enzyme preparation is homogeneous during polyacrylamide gel electrophoresis (pH 7.5 and 7.0) with SDS. The pH-optima of the enzyme thermal stability and of the glutaminase activity are equal to 6.0-8.0. At higher pH values the asparaginase activity increases within the pH range of 4-9. The amino acid composition of glutamin(asparagin)ase has been determined.

Amino Acids↗