Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.4.15.1 (ACE)
18,300 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Endothelial cells are a major source of kininase enzymes including kininase II. Kininase II is situated along the plasma membrane, not as an ecto-enzyme but as an enzyme synthesized by the endothelial cells themselves. However, it is likely that endothelial cells do more than degrade kinins. These cells are contractile and may possess kinin receptors; a possibility supported by the fact that kinins stimulate endothelial cells to form and release prostaglandin-related substances. In addition, we have found that endothelial cells in culture are reactive with antibodies to alpha 2-macroglobulin. Endothelial cells can hydrolyze [3H]Pro-Phe-Arg-anilide, a kallikrein substrate, but the reaction is not inhibited by soya bean trypsin inhibitor (SBTI) or Trasylol. Possibly kallikrein or a related trypsin-like enzyme is bound to alpha 2-macroglobulin and is not free to react with the inhibitors. Thus, endothelial cells can bind and inhibit kallikrein-like enzymes, degrade kinins and respond to kinin stimulation.
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PMID:Endothelial cells and components of the kallikrein-kinin system. 22 4

Two enzymes with tonin-like activity, designated rSMT3 and rSMT4, were purified from rat submandibular glands and another, rPT1, was obtained from the prostate. The three enzyme fractions hydrolysed angiotensin I, angiotensinogen (AG) and synthetic AG(1-14) to form angiotensin II. With angiotensin I as substrate, pH optima were 6.5 for rSMT3, 6.8 for rSMT4 and 7.5 for rPT1. With AG(1-14), the three enzymes had optimal activity at pH 7.5. The three enzymes had negligible activity upon a kallikrein substrate, Ac-Phe-Arg-Nan. The enzymes were inhibited by aprotinin, soybean trypsin inhibitor and phenylmethanesulfonyl fluoride but not by two angiotensin converting enzyme inhibitors, ethylenediaminetetracetic acid or enalaprilat. N-tosyl-L-phenylalanine chloromethyl ketone (1 mM) inhibited rPT1 and rSMT4 but not rSMT3. Molecular weights (SDS-PAGE) were 31,700 for rSMT3, 29,800 for rSMT4 and 28,100 for rPT1. Total activity in the prostate is 150-times lower than in the submandibular gland, where 92% of the tonin activity is related to rSMT4. Physical and chemical properties suggest that rSMT4 is tonin, whereas rSMT3 and rPT1 are tonin-like enzymes which can generate angiotensin II from different substrates.
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PMID:Identification of serine proteinases with tonin-like activity in the rat submandibular and prostate glands. 164 31

Using a bradykinin enzyme immunoassay, we measured the amount of kinin in the peritoneal washings of mice with the kaolin-induced writhing reaction. Simultaneous treatment with captopril, a kininase II inhibitor, significantly increased the kinin level at 1 min after kaolin injection. Soybean trypsin inhibitor injected simultaneously with kaolin almost completely suppressed the kinin level at 1 min with or without treatment of captopril. These results suggest that kinin is released through activation of the plasma kallikrein-kinin system by kaolin, and that kinin could be a main mediator for the writhing reaction.
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PMID:Demonstration of kinin-release in the peritoneal exudate of kaolin-induced writhing in mice. 220 Sep 19

A highly active angiotensin-producing enzyme (enzyme III) was obtained from the serum of bilaterally nephrectomized dogs by acid treatment and ammonium sulfate fractionation. An inactive precursor (proenzyme III) was converted to enzyme III during prolonged storage (or by treatment with acid or with cathepsin G or by incubation at 38 degrees C as described in the following paper). Enzyme III reacted maximally at pH 7.7 and it produced up to 400 ng of angiotensin II/mL serum/h (i.e., amounts 4000 times higher than that generated by the endogenous renin present in serum after bilateral nephrectomy). Enzyme III produced angiotensin II at identical rates when either dog angiotensinogen or angiotensin I was used as substrate, but the rate was 710 times higher with synthetic tetradecapeptide renin substrate. Enzyme III is not identical to renin, cathepsin G, tonin, enzyme I, enzyme II, the calcium-dependent angiotensin I-converting enzyme, or the calcium-independent carboxy peptidase, which acts by sequential cleavage of angiotensin I. Enzyme III was inhibited by alpha-1-antitrypsin, diisopropyl fluorophosphate, and lima bean trypsin inhibitor (hence it is a serine proteinase). It was not inhibited by Captopril, Teprotide, or Enalapril. It had been reported previously that cathepsin G released from neutrophil granulocytes, by producing high local concentrations of angiotensin II, may provide a mobile means for modulating blood flow in tissue microvasculature during the inflammatory response. The present study offers a new, additional pathway, by enzyme III, for a similar rapid formation of angiotensin II from serum protein substrate or angiotensin I.
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PMID:Angiotensin II-producing enzyme III from acidified serum of nephrectomized dogs. 257 42

1 Bradykinin in carrageenin-induced inflammatory pouch fluid was measured by an enzyme immunoassay method. 2 The bradykinin showed a single peak in the 30-60 min period after the challenge and then decreased quickly, and there was a correlation between the bradykinin level and exudation of fluorescein-labelled bovine serum albumin in the first 60 min period. 3 Captopril (an inhibitor of kininase II) elevated both the bradykinin level in the inflammatory pouch fluid and vascular permeability, while DL-2-mercaptomethyl-3- guanidinoethylthiopropanoic acid (an inhibitor of kininase I) had no effect. 4 Soybean trypsin inhibitor (SBTI) inhibited the vascular permeability response in parallel with the decrease in the bradykinin level. 5 A bradykinin-degrading activity appeared in the pouch fluid within 1 h after the challenge and increased with time. 6 In the period of 3.5-4 h, bradykinin levels were suppressed below the sensitivity limit of the assay, i.e. 0.07 nm ml-1, in spite of active generation. This was because degradation of bradykinin was very rapid in this late stage. Nevertheless, bradykinin still played a definite role in sustaining a high level of vascular permeability response in the late stage in conjunction with prostaglandins.
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PMID:Role of bradykinin in the vascular permeability response induced by carrageenin in rats. 283 62

A zinc dependent serratial 56K protease caused enhancement of vascular permeability followed by edema formation when injected into the guinea pig peripheral cornea, the subconjunctival space, or the skin. Because this enhancement was not affected by antihistamine, involvement of the kinin-generating system in this permeability enhancement was investigated. The 56K protease induced permeability much greater extent than that by bradykinin on weight basis, and more so on molar basis. The phenomenon was inhibited by soybean trypsin inhibitor, a well known inhibitor of plasma kallikrein, and also by corn trypsin inhibitor, which is the best inhibitor of the activated Hageman factor. In vitro experiments using numbers of synthetic peptide substrates, the 56K protease exhibited a similar substrate specificity to that of plasma kallikrein. Kallikrein is a known endogenous activator of Hageman factor. The enhancement by 56K protease was greatly augmented by inhibition of kininase II with Glu-Trp-Arg-Pro-Gln-Ile-Pro-Pro-OH (SQ 20,881), suggesting generation of bradykinin. Thus, these results indicate that the enhancement of vascular permeability induced by the 56K protease is caused by an activation of Hageman factor by 56K protease followed by subsequent activation of cascade amplification, and resulted in kinin generation in vivo.
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PMID:Enhancement of vascular permeability upon serratial infection: activation of Hageman factor--kallikrein--kinin cascade. 288 Apr 83

We investigated how bradykinin mediates inflammatory reactions in rats, via measurements of bradykinin by enzyme immunoassay method in inflammatory tissue fluids. Vascular permeability was increased markedly during the first 10 min and then declined quickly after the infusion of a kaolin suspension (10 mg/ml) in 0.8% carboxymethl-cellulose solution into an air pouch formed on the back of rats. Bradykinin in the exudate reached a maximum 5 min after the challenge and then decreased quickly. Local treatment with DL-2-mercaptomethyl-3-guanidinoethylthiopropanoic acid, an inhibitor of kininase I, and captopril, an inhibitor of kininase II in the first 10-min period, each enhanced the vascular permeability increase accompanied by the elevation of the bradykinin level, whereas soybean trypsin inhibitor, a plasma kallikrein inhibitor, lowered both vascular permeability and bradykinin. When applied in the period of 3.5 to 4 hr after the challenge, only the kininase II inhibitor was effective in elevating both vascular permeability and the bradykinin level, whereas soybean trypsin inhibitor was ineffective on vascular permeability. A bradykinin-degrading activity appeared in the exudate as early as 10 min after the challenge. These results suggest that bradykinin plays an essential role for the sudden rise of the vascular permeability observed immediately after the infusion of kaolin suspension. In the later stage (3.5-4 hr), bradykinin level remained below the assay limit of 0.07 ng/ml in spite of its active generation, presumably because of its rapid degradation by the kininases, although it still played a definite role in the vascular permeability increase.
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PMID:Role of bradykinin generating and degrading systems in the vascular permeability response induced with kaolin in rats. 332 Mar 43

Cultured bovine pulmonary artery endothelial cells contain a second peptidyl dipeptidase, distinct from angiotensin-converting enzyme, present in an inactive form associated with a non-dialyzable inhibitor. Partial purification by glycine affinity chromatography separates enzyme from inhibitor to yield a preparation which hydrolyzes angiotensin-1, bradykinin, substance P, atriopeptin-2, enkephalin and Hip-His-Leu. This enzyme is resistant to inhibition by lisinopril, captopril, thiorphan, phosphoramidon, soybean trypsin inhibitor, PMSF and aminopeptidase and carboxypeptidase inhibitors, but is inhibited by EDTA.
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PMID:Conversion of angiotensin-1 to angiotensin-2 by a latent endothelial cell peptidyl dipeptidase that is not angiotensin-converting enzyme. 351 10

The major cathepsin B isozyme CB-I purified from porcine spleens was studied for its specificity against various peptide and denatured protein substrates. The enzyme degraded all the peptide substrates by an exopeptidase activity. The substrates were degraded mainly by a dipeptidyl carboxypeptidase activity of the enzyme except for angiotensin I, from which a COOH-terminal leucine residue was released. The enzyme failed to hydrolyze peptides having a proline or cysteic acid in the COOH-terminal, penultimate, and antepenultimate positions. Reduced and carboxymethylated soybean trypsin inhibitor was degraded by the same dipeptidyl carboxypeptidase action of cathepsin B. No significant endopeptidase activity was observed. These results do not support the general assumption that cathepsin B has both endo- and exopeptidase activities, neither do these observations support the postulation that cathepsin B might be involved in the in vivo proteolytic processing of protein precursors. We propose that the biological role of this enzyme is mainly the degradation of tissue proteins in lysosomes.
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PMID:Porcine spleen cathepsin B is an exopeptidase. 352 89

Vibrio vulnificus protease enhanced hypodermic vascular permeability when injected into the dorsal skin of a guinea pig. Enhancement of permeability was observed within 2 min, and the permeability-enhancing reaction terminated at about 10 min postinjection. The permeability-enhancing reaction was greatly augmented by simultaneous injection of a kininase II inhibitor, whereas the reaction was inhibited by soybean trypsin inhibitor, a well-known inhibitor of plasma kallikrein. Furthermore, in vitro activation of plasma prekallikrein to kallikrein by V. vulnificus protease was observed. These results indicate that V. vulnificus protease enhances vascular permeability through activation of the plasma kallikrein-kinin system which generates bradykinin, factor in edema formation.
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PMID:Activation of the plasma kallikrein-kinin system by Vibrio vulnificus protease. 364 35


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