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:3.4.23.5 (cathepsin D)
4,130 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Eglin C is a polypeptide inhibitor of the neutral proteases elastase and cathepsin G. We have investigated its action in traumatic shock in rats. Eglin C (2 mg/kg) given following trauma prolonged survival time from 2.3 +/- 0.5 h to 3.6 +/- 0.4 h (p less than 0.05) in traumatized rats. Although eglin C treatment had no significant effect on the increase in plasma cathepsin D activity, eglin C administration significantly blunted plasma myocardial depressant factor (MDF) accumulation, 54 +/- 3 vs 79 +/- 8 U/ml (p less than 0.02). Our findings indicate a potential role for neutral proteases in toxic factor formation.
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PMID:Beneficial effects of a neutral protease inhibitor in traumatic shock. 401 46

Immunization with renin from the kidneys of hog, beef, dog, rabbit and man induced the formation of a highly active enzyme (enzyme I) in the serum of dogs, guinea pigs, rabbits and rats. Enzyme I produces angiotensin I maximally at pH 4.7, up to 2900 ng/ml serum/h, i.e. at a rate 2500 times higher than the endogenous renin of normal serum. At pH 7.2 the angiotensin I production by enzyme I is about 16 to 28 times higher than that of plasma renin. Enzyme I is produced by immunization with renin and not by other kidney proteins. Enzymatically-active renin is required and separate mechanisms are involved in the formation of enzyme I and antirenin. Enzyme I is not identical to renin, pepsin, cathepsin D, plasmin, tonin or cathepsin G and it is inhibited by pepstatin, but not by diisopropyl fluorophosphate.
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PMID:Angiotensin-producing enzyme I of serum: formation by immunization with renin. 609 39

Extracts of rheumatoid synovial tissue obtained at surgical synovectomy contained neutral proteinases as well as cathepsin D. The neutral proteinase activity was particle-bound but could be solubilized by 1 M MgCl2. About half of the solubilized activity adsorbed to aproptinin-Sepharose at pH 7.5 and was desorbed at pH 3.3. This activity was shown to be due to leukocyte elastase and cathepsin G by enzymological and immunological criteria. The neutral proteinase activity that did not adsorb to aprotinin-Sepharose was not due to elastase or cathepsin G. It was able to hydrolyse proteoglycan and was inhibited by diisopropylfluorophosphate, soybean and lima bean trypsin inhibitors. It was, therefore, a serine proteinase. Its inhibition characteristics were different from those of plasmin, kallikrein or thrombin. All of the neutral proteinase activity of synovial extracts was attributable to serine proteinases, no evidence of metallo-proteinases was found. The possible role of the neutral proteinases in the degradation of the matrix of cartilage is discussed. A simple procedure for purifying leukocyte elastase and cathepsin G is described as well as the raising of specific antisera to these enzymes.
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PMID:Identification of proteinases in rheumatoid synovium. Detection of leukocyte elastase cathepsin G and another serine proteinase. 615 6

The proteolytic activity in homogenates and extracts of subcellular fractions prepared from subcutaneous Lewis lung carcinoma was determined using proteins and synthetic peptides as substrates. The presence of cathepsin D, plasminogen activator, cathepsin B-, cathepsin G- and elastase-like enzymes was observed. No difference was revealed between the proteolytic activity in homogenates of Lewis lung carcinoma, at the growth stage examined, and in homogenates of normal lung. High specific activities were found in the lysosomal extract, whereas decreasing activities were found in the nuclear extract, the homogenate and the postlysosomal mitochondrial supernatant; no active or trypsin-activatable collagenase activity was detected. The presence in the tumor tissue of these enzymatic activities is in agreement with their proposed role in the process of metastasis. The lack of differences between homogenates of tumor and normal lung tissue suggests that the use of whole cells is required to selectively study tumor proteinases specifically involved in tumor malignancy.
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PMID:Methodologic problems encountered in the assay of proteinases in Lewis lung carcinoma, a mouse metastasizing tumor. 629 35

There are two types of enzymes in tissues leading to angiotensin formation: a) those resulting in the formation of angiotensin I, such as renin and cathepsin D, the presence of which is now well established for brain tissue and b) Those leading to the direct formation of angiotensin II without the angiotensin I step, such as cathepsin G and tonin. Recent findings concerning tonin, a serine protease, are described: a) 80% of its amino acid sequence, b) its different characteristics from other serine proteases, from renin, cathepsin D and the angiotensin I converting enzyme, c) the activation of inactive renin, d) its involvement in the 1K-1C hypertensive rats, e) the demonstration of its presence in the distal tubular cells of the rat kidney, and finally, f) its presence in urine and the influence of age and of sodium intake on its urinary excretion.
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PMID:Extrarenal angiotensin-forming enzymes. 631 65

The proteinase activity of the low molecular weight cytotoxin of Entamoeba histolytica was correlated with its cytotoxicity. Gel-filtered amebal toxin (mol wt 10-30,000) proteinase activities could be assayed on azocasein at pH 6 or on hemoglobin at pH 4.5. Proteinase activity was inhibited by serum fractions, thiol reagents, heavy metals, leupeptin, and antipain. The cytotoxic activity of gel-filtered amebal toxin was inhibited by serum fractions, leupeptin, and antipain. Increased proteinase and cytotoxic activity was produced by treatment with cysteine. These data support the action of a thiol proteinase in the production of cytopathic effects by gel-filtered amebal toxin in vitro. The cytotoxic and proteinase activities were further purified using a combination of column chromatography and preparative isoelectric focusing. Two low molecular weight cytotoxins with proteinase activity on both substrates were isolated. The major cytotoxin had an isoelectric point of 4.5 and a molecular weight of 22,000; the other cytotoxin had a basic isoelectric point. These substances may be cathepsin B-like proteinase and elastase or cathepsin G-like proteinases of E. histolytica. The major proteinase activity in the high molecular weight fraction was not cytotoxic. The isoelectric points of the high molecular weight proteinase activities corresponded to that of mammalian cathepsin D. The major cell rounding cytotoxic activity of E. histolytica extracts in vitro is probably due to the activity of a thiol-containing cathepsin B-like proteinase.
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PMID:Proteinase activities of Entamoeba histolytica cytotoxin. 632 55

1. Proteolytic enzymes are likely to play the main role on the proteoglycan (PG)-degrading activity of rheumatoid synovium. In this paper, the presence of cathepsin D, cathepsin B, lysosomal elastase and cathepsin G in rheumatoid synovium is established by isolation, purification, and characterization of these proteases. 2. The degradation of MgCl2-extracted PG from bovine nasal cartilage was performed by using these proteases and the property of the products was studied by the viscosity, Sepharose CL-4B chromatography, Agarose/polyacrylamide-gel electrophoresis, hexosamine analysis and amino acids analysis. 3. These proteases reduced the viscosity of PG solutions and the reaction was inhibited by addition of pepstatin, antipain, elastatinal and chymostatin for each protease. 4. The size and chemical composition of the degradation products varied with the different proteases. Of the four proteases, cathepsin G produced the largest glycosaminoglycan multi-chain peptides and cathepsin B produced the smallest contained chondroitin single-chain peptide. Each protease specifically split PG core protein and the degradation products particularly indicated the characteristic structure of core peptides. 5. The results suggest that these proteases may be contributed to the breakdown of cartilage PG in rheumatoid arthritis.
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PMID:[Studies on degradation of cartilage proteoglycan by rheumatoid synovial tissue. Part II: On the property of acid and neutral proteases obtained from rheumatoid synovial tissue (author's transl)]. 703 96

DMP 323 is a potent inhibitor of the protease of human immunodeficiency virus (HIV), with antiviral activity against both HIV type 1 and HIV type 2. This compound is representative of a class of small, novel, nonpeptide cyclic urea inhibitors of HIV protease that were designed on the basis of three-dimensional structural information and three-dimensional database searching. We report here studies of the kinetics of DMP 323 inhibition of the cleavage of peptide and HIV-1 gag polyprotein substrates. DMP 323 acts as a rapidly binding, competitive inhibitor of HIV protease. DMP 323 is as potent against both peptide and viral polyprotein substrates as A-80987, Q8024, and Ro-31-8959, which are among the most potent inhibitors of HIV protease described in the literature to date. Incubation with human plasma or serum did not decrease the effective potency of DMP 323 for HIV protease, suggesting that plasma protein binding is of a low affinity relative to that of HIV protease. DMP 323 was also assessed for its ability to inhibit the mammalian proteases renin, pepsin, cathepsin D, cathepsin G, and chymotrypsin. No inhibition of greater than 12% was observed for any of these enzymes at concentrations of DMP 323 that were 350 to 40,000 times higher than that required to inhibit the viral protease 50%.
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PMID:Potency and selectivity of inhibition of human immunodeficiency virus protease by a small nonpeptide cyclic urea, DMP 323. 797 96

No single protease has emerged that possesses all the expected properties for beta-secretase, including brain localization, appropriate peptide cleavage specificity, and the ability to cleave amyloid precursor protein exactly at the amino-terminus of beta-amyloid peptide. We have isolated and purified a brain-derived activity that cleaves the synthetic peptide substrate SEVKMDAEF between methionine and aspartate residues, as required to generate the amino-terminus of beta-amyloid peptide. Its molecular size of 55-60 kDa and inhibitory profile indicate that we have purified the metalloprotease EC 3.4.24.15. We have compared the sequence specificity of EC 3.4.24.15, cathepsin D, and cathepsin G for their ability to cleave the model peptide SEVKMDAEF or related peptides that contain substitutions reported to modulate beta-amyloid peptide production. We have also tested the ability of these enzymes to form carboxyl-terminal fragments from full-length, membrane-embedded amyloid precursor protein substrate or amyloid precursor protein that contains the Swedish KM --> NL mutation. The correct cleavage was tested with an antibody specific for the free amino-terminus of beta-amyloid peptide. Our results exclude EC 3.4.24.15 as a candidate beta-secretase. Although cathepsin G cleaves the model peptide correctly, it displays poor ability to cleave the Swedish KM --> NL peptide and does not generate carboxy-terminal fragments that are immunoreactive with amino-terminal-specific antiserum. Cathepsin D does not cleave the model peptide or show specificity for wild-type amyloid precursor protein; however, it cleaves the Swedish "NL peptide" and "NL precursor" substrates appropriately. Our results suggest that cathepsin D could act as beta-secretase in the Swedish type of familial Alzheimer's disease and demonstrate the importance of using full-length substrate to verify the sequence specificity of candidate proteases.
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PMID:Evaluation of cathepsins D and G and EC 3.4.24.15 as candidate beta-secretase proteases using peptide and amyloid precursor protein substrates. 863 67

The alternatively spliced type III connecting segment (IIICS) of fibronectin (Fn) contains an amino acid sequence, CS-1, which is recognized by the integrin receptor, alpha 4 beta 1. Plasma Fn inhibits alpha 4 beta 1-dependent binding of lymphocytes and monocytes to CS-1 containing Fn derivatives poorly, suggesting limited exposure of the CS-1 sequence in Fn. To test the availability of CS-1 in plasma Fn, an antibody was raised to the synthetic peptide CS-1. The CS-1 sequence was found to be minimally exposed in plasma Fn; and immobilization of Fn, a model of matrix deposition, caused only a modest increase in its exposure. Digestion of Fn with selected proteases, however, induced substantial expression of the CS-1 sequence. The acid protease cathepsin D generated fragments of 31-33.5 kDa from the COOH-terminal heparin-binding domain of Fn which possessed high immunoreactivity with anti-CS-1. Digestion of Fn with cathepsin B also resulted in the exposure of CS-1 sequence in a 140 kDa fragment. Although the digestion of Fn with neutral proteases (neutrophil elastase, cathepsin G, chymotrypsin, trypsin) generated fragments from the COOH-terminal heparin-binding domain of similar molecular weight as with cathepsin D, the exposure of CS-1 did not occur. Exposure of the CS-1 region by the cathepsins was supported by cell adhesion experiments; digestion of Fn with cathepsins D and B transformed inert plasma Fn to an effective inhibitor of adhesion of lymphoblastoid B and T cells (Ramos, Jurkat, Molt-4) to an immobilized CS-1 conjugate. These results suggest that exposure of the CS-1 sequence in plasma Fn by proteolysis with cathepsins D and B, enzymes implicated in several pathological processes, may serve a regulatory function in cell adhesion. The adhesive function of the CS-1 region in intact Fn appears to be suppressed by the native conformation of the molecule.
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PMID:Proteolysis regulates exposure of the IIICS-1 adhesive sequence in plasma fibronectin. 871 84


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