Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.24.3 (collagenase)
 18,340 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Extracts of highly purified lysosomes from rat liver were examined for their ability to degrade native collagen and thermally denatured collagen at pH values between 3.5 and 7.0. After a 24-h digestion at 36 degrees with the lysosomal extract at a pH of 5.5 or lower (collagen/lysosomal protein; 2/1 or 8/1), both native and denatured collagen were degraded to an extent equivalent to 60 to 70% of that observed upon total acid hydrolysis in 6 N HCl as measured by the ninhydrin reaction (570 nm). At a pH of 6.0, native collagen and denatured collagen were degraded by the mixture of lysosomal proteinases to 11% and 40% of total acid hydrolysis, respectively. At pH 6.5 AND 7.0, the corresponding values were 3% versus 33% and 0.3% versus 11%, respectively. Fragments of collagen (TCA and TCB) are produced when mammalian collagenase degrades native collagen at 25 degrees. These fragments were degraded by the lysosomal extract at 36 degrees to an extent equivalent to 28% and 8% of total acid hydrolysis at pH 6.5 and 7.0, respectively. The experiments at pH 6.5 and 7.0 were done using a collagen/lysosomal protein ratio of 2/1. At pH 5.0 (a pH which is found within secondary lysosomes), the lysosomal extracts degraded collagen to a mixture of free amino acids and small peptides. Amino acid analysis established that approximately 30% of the amino acid residues of the collagen appeared in the lysosomal hydrolysate as free amino acids. Hydroxyproline and perhaps hydroxylysine were the only amino acids found in collagen which did not appear at least to some extent as the free amino acid in this hydrolysate.
J Biol Chem 1976 Sep 10
PMID:Digestion of native collagen, denatured collagen, and collagen fragments by extracts of rat liver lysosomes. 0 59

The acyl-CoA:sn-glycerol-3-phosphate acyltransferase (EC 2.3.1.15) (glycerol-P acyltransferase) and acyl-CoA:dihydroxyacetone phosphate acyltransferase (EC 2.3.1.42) (DHAP acyltransferase) activities were investigated in vitro in order to evaluate the quantitative contribution of the glycerol-P and DHAP pathways for the synthesis of triacylglycerols in isolated fat cells and to test the hypothesis that these two activities may be dual catalytic functions of a single enzyme. More than 85% of both acyltransferase activities was associated with the microsomal subcellular fraction. The microsomal glycerol-P acyltransferase activity showed an apparent Km of 8 muM for glycerol-P with a Vmax of 15.6 nmol/min/mg, while the DHAP acyltransferase activity showed an apparent Km of 40 muM for DHAP with a Vmax of 9.7 nmol/min/mg. Glycerol-P was a competitive inhibitor (Ki = 7.2 muM) of the DHAP acyltransferase, and DHAP was a competitive inhibitor (Ki = 92 muM) of the glycerol-P acyltransferase. The two acyltransferase activities showed virtual identity in their pH dependence, acyl-CoA chain length dependence, thermolability, and inactivation by N-ethylmaleimide. Trypsin, detergents, collagenase, phospholipases, and various salts and organic solvents also had similar effects on both activities. Taken as a whole, the data strongly suggest that the microsomal glycerol-P and DHAP acyltransferase activities actually represent dual functions of a single enzyme. Calculations based on the above kinetic constants and previously reported glycerol-P and DHAP pools in adipocytes suggest that the in vivo ratio of glycerol-P to DHAP acylation should be greater than 24:1.
J Biol Chem 1976 Sep 25
PMID:Triacylglycerol synthesis in isolated fat cells. Evidence that the sn-glycerol-3-phosphate and dihydroxyacetone phosphate acyltransferase activities are dual catalytic functions of a single microsomal enzyme. 0 98

A total of 160 1-2 day old chickens were fed a 2% cholesterol diet for a period of 8 to 42 days and compared with an equal number of controls. Aortas were analyzed for various indexes of reactivity of connective tissue, cholesterol content and scanning electron microscopy (SEM) characteristics of the endothelial lining. Cholesterol feeding for a period up to 6 weeks resulted in doubling the level of serum cholesterol. It was, however, without effect on the activity of prolyl hydroxylase, lysyl oxidase, collagenase and collagen content in the aortic wall. As early as 3 weeks of feeding significant changes occurred in total and esterified cholesterol content. At the same time endothelial cells were characteristically contracted with several long cytoplasmic elongations and protrusions. A significant decrease of activity of the above enzymes was found in aortic tissue with increased age of the chicken. Collagen content in aortas increased with age of chickens. It is concluded that cholesterol as an atherogenic agent induces marked changes in endothelial cells and lipids of chicken aorta at earlier periods, prior to the activation of connective tissue.
Atherosclerosis 1976 Sep
PMID:Early changes in the arterial wall of chickens fed a cholesterol diet. 0 48

A neutral proteinase secreted by rabbit synovial fibroblasts in parallel with specific collagenase was partially purified by ion-exchange chromatography. At pH 7.6 this proteinase degraded 35S-labelled bovine nasal proteoglycan and azo-casein. The enzymic activity was inhibited by EDTA, 1,10-phenanthroline and serum, whereas di-isopropyl phosphorofluoridate and soya-bean trypsin inhibitor had little effect. By gel filtration the apparent mol.wt. of the enzyme was 25000. The fibroblast neutral proteinase was compared with the proteoglycan-degrading neutral proteinases of rabbit polymorphonuclear-leucocyte granules. Two distinct activities were found in the granules: one was inhibited by soya-bean trypsin inhibitor and the other by EDTA. The proteoglycan-degrading proteinases of rabbit fibroblasts and polymorphonuclear leucocytes at acid pH also were examined. Both cathepsin D and a thiol-dependent proteinase contributed to the degradation of proteoglycan at pH 4.5.
Biochem J 1978 Sep 01
PMID:Proteoglycan-degrading enzymes of rabbit fibroblasts and granulocytes. 3 Apr 51

A specific collagenase (EC 3.4.24.3) has been found and purified from serum-free culture medium of 11095 epidermoid carcinoma of rat prostate. The molecular weight of this collagenase was estimated at 71 000 and the pH optimum was approx. 7. At 26 degrees C, the collagenase cleaved collagen at a site 3/4 the length from the N-terminus. At 37 degrees C, this collagenase degraded collagen to smaller peptides. The enzyme activity was inhibited by serum, cysteine and EDTA, but not by protease inhibitors. The presence of collagenase in rat tumor tissue suggests that this enzyme might play a significant role in tissue invasion by cancer cells.
Biochim Biophys Acta 1979 Sep 12
PMID:Collagenase activity in cultures of rat prostate carcinoma. 3 9

A model system consisting of highly purified lysyl oxidase and reconstituted lathyritic chick bone collagen fibrils was used to study the effect of collagen cross-linking on collagen degradation by mammalian collagenase. The results indicate that synthesis of approx. 0.1 Schiff-base cross-link per collagen molecule results in a 2--3-fold resistance to human synovial collagenase when compared with un-cross-linked controls or samples incubated in the presence of beta-aminopropionitrile to inhibit cross-linking. These results confirm previous studies utilizing artificially cross-linked collagens, or collagens isolated as insoluble material after cross-linking in vivo, and suggest that increased resistance to collagenase may be one of the earliest effects of cross-linking in vivo. The extent of intermolecular cross-linking among collagen fibrils may provide a mechanism for regulating the rate of collagen catabolism relative to synthesis in normal and pathological conditions.
Biochem J 1979 Sep 01
PMID:Native cross-links in collagen fibrils induce resistance to human synovial collagenase. 4 86

Cardiac myocytes from adult rat were isolated by heart perfusion in the presence of collagenase and incubated in the absence and presence of oxygen. As a result of anoxia, there was a gradual increase in plasma membrane permeability, noted as an increase in succinate-stimulated oxygen uptake, a decrease in trypan blue exclusion frequency, a leakage of cytosolic lactate dehydrogenase activity and an increased proportion of swollen, irregularly contracting myocytes. The contractions of the damaged myocytes resembled the known non-physiologic contractions of the heart, i.e. extrasystoles, arrhythmia, fibrillation or block. After different periods of time of anoxia myocyte pellets were fixed in formalin, sectioned and examined by light microscopy. The appearances of the myocytes in suspension were compared with those in paraffin-embedded sections. Special attention was given to the hematoxylin basic fuchsin picric acid stain and it was noted that the basic fuchsin was taken up by contracted or damaged myocytes, which according to their morphology in suspension revealed irregular contractions, but not by undamaged or necrotic myocytes.
Acta Pathol Microbiol Scand A 1978 Sep
PMID:Comparison of anoxic changes in isolated rat cardiac myocytes in suspension and in histological sections. 8 68

Three different types of neutral proteases related to collagen metabolism have been found in the granule fraction of human leucocytes from normal adults, using collagen, gelatin, and synthetic peptides as substrates. These are collagenase, an enzyme showing a potent hydrolytic activity against gelatin but little against native collagen, and one splitting the cross-links region of collagen. Their molecular weights were estimated to be about 75,000 150,000, and 25,000, respectively, by gel chromatography. The former two enzymes were inhibited by a alpha2-macroglobulin and ethylenediaminetetraacetate, but not by alpha1-proteinase inhibitor (alpha1-antitrypsin) or phenylmethylsulfonylfluoride, while the latter enzyme, associated in behavior with an enzyme hydrolyzing succinyl-(l-alanyl)3-p-nitroanilide, was inhibited by alpha1-proteinase inhibitor, alpha2-macroglobulin, and phenylmethylsulfonylfluoride, but not by ethylenediaminetetraacetate. A possible cooperative function of these enzymes in collagen catabolism is discussed.
J Biochem 1978 Sep
PMID:Human leucocyte neutral proteases, with special reference to collagen metabolism. 8 54

Why the cornea ulcerates, in the sense of what goes awry, may be related to the trapping of wound healing in a phase of proteolytic debridement related to a persistent epithelial defect. The initial avascularity of the cornea makes it particularly vulnerable to proteolytic damage. Studies on the biochemistry and cell biology of corneal ulceration have indicated that sequential interactions occur which result in the generation of collagenase activity and the development of ulceration. It is likely that the interactions are susceptible to intervention; and it is thought that eventual, successful treatment of corneal ulceration will require a complex therapy, with interventions at multiple sites of regulation.
Trans Ophthalmol Soc U K 1978 Sep
PMID:Regulation of collagenase. Therapeutic considerations. 8 26

Basement membrane (type IV) collagens were extracted from a mouse tumour with acetic acid and from human placenta after limited enzymatic digestion. Antisera were produced against both collagens in rabbits and guinea-pigs and examined by various assays. These antisera were found to be specific for basement membrane collagen and showed little or no cross-reactions with the interstitial collagens, types I, II and III or with human placenta collagen consisting of alpha A and alpha B chains. Varying degrees of cross-reaction were observed between antisera to human and mouse type IV collagen. Immunochemical analyses demonstrated the presence of three distinct determinants in the tumour type IV collagen. Rabbit antisera against this antigen reacted with either collagenase-resistant segments or with a collagenous, disulphide-bonded segment (P3). Guinea-pig antisera recognized primarily antigenic determinants in the P3 segment. Antisera to placenta type IV collagen reacted with another collagenous, pepsin fragment (P1) which lacks disulphide bonds. These antisera showed complete cross-reaction with collagenous alpha 1 (IV) chains prepared from pepsin-digests of human placenta and bovine lens capsule.
Immunology 1979 Sep
PMID:Immunochemical study on basement membrane (type IV) collagens. 9 54


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