[Effect of SQ-20881, an inhibitor of carboxycathepsin (angiotensin I-converting enzyme), on peripheral circulation during the early postresuscitation period].
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Animals↗
Biomedical subjects
V N Orekhovich
Publications and source records attributed to V N Orekhovich.
[Kininogenase activity of cathepsins D].
The kininogenase activity of highly purified preparations of cathepsins D from human liver and spleen, leukemic infiltrate obtained from patients with myeloic leukemia, and from chicken liver was studied. It was found that pepstatin, a specific inhibitor of carboxylic proteinases, inhibits this activity of cathepsins D. Interaction of chicken liver cathepsin D with human plasma substrate, which is possibly a low molecular weight kininogen (Ks = 1.3.10(-7) M) results in a production of the bradikinin analog methionyl-lysyl-bradikinin. The role of cathepsins D as potent inflammatory agents responsible for the generation of biologically active peptides--mediators of inflammation from the protein substrates including kininogens under desintegration of lysosomes is discussed.
Animals↗
[Effect of "group specific" inhibitors on highly purified adenohypophyseal prolyl-(D,L)-alanine peptidohydrolase].
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Animals↗
Preparation and some properties of highly purified human serum kallikrein.
A 3000--6000-fold purified kallikrein was obtained from human serum in 10--25% yield by chromatography on QAE-Sephadex A-50, Molselect CM-50 and on soybean trypsin inhibitor (SBTI)-AH-Sepharose 4-B. The enzyme had a specific activity of 14--23 U, as measured by BAEE hydrolysis. Some properties of highly purified kallikrein are described.
Chromatography, Affinity↗
Preparation and some properties of human serum kallikrein immobilized on ARM-Sepharose.
A highly purified human serum kallikrein immobilized on CH-Sepharose 4-B was obtained. KM values for N-benzoyl-L-arginine ethyl ester and N-tosyl-L-arginine methyl ester hydrolysis of this preparation were 1.10 x 10(-3) M and 3.6 x 10(-4) M, respectively; pH optimum of hydrolysis of these esters were found to be 8.2 and 8.5, respectively. The immobilized kallikrein possessed kininogenase activity and was capable of activating prekallikrein.
Arginine↗
[Effect of propyl-(D,L)-alanine peptidylhydrolase on vasoactive peptides].
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Angiotensin I↗
[Structure, functions and the biosynthesis of proteins and the problems of molecular pathology].
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Animals↗
[Activation of prekallikrein from human blood serum by different activators].
It was shown that the activated Hageman factor and its active fragment convert a greater amount of prekallikrein into kallikrein than is observed under the effects of trypsin and kallikrein. The latter two enzymes convert from 30 to 60% of the Hageman factor-activated prekallikrein and its active fragment. A possible existence of two prekallikrein forms is discussed. A mechanism of interaction between individual components of the kininogenase system and their activators is discussed.
Enzyme Activation↗
[Inhibitors of cathepsin R (ribosomal proteinase). Polyamines as natural inhibitors of the proteinase].
The effects of potential inhibitors on the activity of neutral ribosomal proteinase--cathepsis R--were studied. It was found that cathepsin R belongs to the group of serine enzymes. The polyamines spermine and spermidine, which are inherently present in the ribosomes, are natural reversible inhibitors of cathepsin R. Upon separation of the enzyme from the inhibitors the proteinase displays a high activity. The effects of polyamines on the proteinase activity may either be direct or mediated via RNA. The enzyme activity can also be controlled by amino acids. Approximately 2/3 of cathepsis R were found in a latent state.
Animals↗
[Cathepsins D from normal and some human neoplasms].
Cathepsins D were isolated from human liver and spleen, from three malignant tumours (kidney cancer, sarcoma, spleen tumour caused by chronic myeloleucosis) and from one non-malignant tumour (uterine myoma). The isolation procedure involved adsorption on pepstatin-Sepharose and gel-filtration on Sephadex G-100. A comparative study of the properties of these enzymes was carried out. The molecular weights, specific proteolytic activity toward hemoglobin and the synthetic hexapeptide Acetyl-Val-Val-Leu-Ser-Leu-Thr, carbohydrate content and type of dissociation of the molecules into polypeptide fragments during electrophoresis in the presence of DS-Na were determined. All the enzymes under study had molecular weights of about 45 000 except uterine myoma cathepsins (mol. weight 95 000). The latter cathepsin also differed from the other enzymes in its higher carbohydrate content.
Cathepsins↗
[Molecular structure of aminopeptidase A from bovine kidney].
Using gel-filtration through Sephadex G-100 and polyacrylamide gel electrophoresis in the presence of 0,5% sodium dodecyl sulfate, it was found that aminopeptidase A has a molecular weight of 65 000 +/- 2000 and is made up of two subunits with mol. weights of 33 000 +/- 2000. Each subunit consists of two polypeptide chains with mol. weights of 22 000 +/- 2000 and 12 000. During enzyme dissociation into subunits the aspartylnaphtylamidase activity is lost, while the glutamylnaphtylamidase activity is retained.
Aminopeptidases↗
[Isolation and properties of bovine kidney aminopeptidase A].
Aminopeptidase A, which specifically hydrolyses N-terminal dicarbonic amino acid residues containing free alpha-amino groups, is isolated from bovine kidney. The enzyme is 500-fold purified and is homogenous under electrophoresis and ultracentrifugation. Aminopeptidase A has pH optimum of 7.5, it is activated with Ca2+ and inactivated with EDTA. Its molecular weight is 53000. The enzyme hydrolyses alpha-L-aspartyl-beta-naphtylamide and splits peptides having N-terminal glycine, lysine, arginine and alanine are hydrolyzed by the enzyme much slower. Aminopeptidase A does not attack alpha-L-alanyl-beta-naphtylamide, leucineamide, insulin, peptides with blocked N-terminal amino acid and peptides which have proline to be the second N-terminal amino acid.
Aminopeptidases↗
[On the localization of ribosomal proteinase].
The localization of proteolytic activity in rat liver ribosomes was studied. 40S and 60S subparticles were obtained upon dissociation of polyribosomes by puromycin. It was shown that the proteolytic activity is associated with small subparticles or with proteins removed from the latter.
Animals↗
[Enzymatic clevage of the peptide bonds formed by amino acid D-isomers].
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Alanine↗
[Specificity of neutral ribosomal protease].
The specificity of the ribosomal proteinase was studied using a variety of substrates: nascend peptides, ribosomal proteins, B-chain of insulin and some synthetic peptides (the heptapeptide Gly-Phe-Phe-Tyr-Thr-Pro-Lys; the hexapeptide Gly-Phe-Leu-Gly-Phe-Leu and the CBZ-hexapeptide; the tripeptide Phe-His-Leu and the CBZ-tripeptide). It was shown that in the heptapeptide tested the enzyme cleaved most rapidly the Phe-Tyr bond; the Phe-Phe bond was cleaved less rapidly. The rest of the peptide bonds in the heptapeptide were also cleaved and by the end of the incubation the cleavage was complete. All the other substrates tested also underwent complete degradation. The data obtained allowed us to classify the enzyme with the group of endopeptidases with broad specificity of action. The possibility cannot be excluded that the broad specificity observed is due to the presence of more than one enzyme on the polyribosomes.
Endopeptidases↗
Effect of kininogen on the activity of the kallikreinogen-kallikrein system of human blood serum.
In experiments with kallikreinogen, kallikrein and kininogen preparations from human blood serum partially purified on QAE-Sephadex A-50, CM-Sephadex and Sephadex G-200 it was established that N-benzoyl-L-arginine ethyl ester (BAEE)-esterase activity of kallikrein and the process of autoactivation of kallikreinogen are inhibited by kininogen, especially by its high-molecular form.
Arginine↗
[Study of the carbohydrate component of cathepsin D].
A content of neutral sugars and N-acetyl-glucosamine in homogeneous cathepsin D preparations from a variety of vertebrate organs was determined. A more detailed study of the carbohydrate component was carried out with chicken liver cathepsin D preparation. It was shown that carbohydrates constitute 20% of the molecule of this cathepsin and contain glucosamine (11.6%) and mannose (10%). Removal of the major portion of the carbohydrates by treatment with mixture of glycosidases did not lead to any significant decrease of biological activity. This finding suggests that the carbohydrate component is not essential for the biological activity of the enzyme. Analysis of distribution of carbohydrates in the peptides of the trypsin hydrolyzate of cathepsin D allows conclusion that the enzyme molecule has several carbohydrate chains attached to different sites of the molecule.
Animals↗
[Effect of kininogen on the activity of human blood serum kininogenase system].
The inhibitory effect of kininogen (especially its high molecular form) on kallikrein esterase activity and on the process of kallikreinogen auto-activation is demonstrated. Kallikreinogen and kininogen from human blood serum partially purified on QAE-Sephadex. CM-Sephadex and G-200 Sephadex were used in experiments.
Enzyme Activation↗