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:3.4.24.3 (collagenase)
18,340 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The 72- and 92-kDa type IV collagenases are members of a group of secreted zinc metalloproteases. Two members of this family, collagenase and stromelysin, have previously been localized to the long arm of chromosome 11. Here we assign both of the two type IV collagenase genes to human chromosome 16. By sequencing, the 72-kDa gene is shown to consist of 13 exons, 3 more than have been reported for the other members of this gene family. The extra exons encode the amino acids of the fibronectin-like domain which has so far been found in only the 72- and 92-kDa type IV collagenase. The evolutionary relationship among the members of this gene family is discussed.
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PMID:On the structure and chromosome location of the 72- and 92-kDa human type IV collagenase genes. 185 24

Sequence-based inhibitors of collagenase bearing an hydroxamate group capable of chelating the active site zinc atom were synthesized and tested. The effect of one of these molecules (RP 59794; Ki about 10(-8) M) on the formation of the TIMP: collagenase complex was also tested. RP 59794 blocks complex formation and can partially dissociate established TIMP: collagenase complexes. It exhibits the same stereospecificity in this activity as in its inhibition of collagenase suggesting that TIMP and RP 59794 both interact with the active site region of collagenase.
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PMID:Low molecular weight, sequence based, collagenase inhibitors selectively block the interaction between collagenase and TIMP (tissue inhibitor of metalloproteinases). 196 13

Pseudomonas aeruginosa elastase is a zinc metalloproteinase which is released during P. aeruginosa infections. Pseudomonas keratitis, which occurs following contact lens-induced corneal trauma, can lead to rapid, liquefactive necrosis of the cornea. This destruction has been attributed to the release of both host-derived enzymes and the bacterial products P. aeruginosa elastase, alkaline protease, exotoxin A, and lipopolysaccharide endotoxin. A synthetic metalloproteinase inhibitor, HSCH2 (DL)CH[CH2CH(CH3)2]CO-Phe-Ala-NH2, which we previously showed to be a potent inhibitor of corneal collagenase and alkali-induced corneal ulceration, was tested as a potential inhibitor of P. aeruginosa elastase. Inhibition constants (Kis) for the resolved diastereomers were determined with the chromogenic substrate furylacryloyl-glycyl-L-leucyl-L-alanine. One isomer had a Ki of 0.3 microM, while the other had a Ki of 0.4 microM. The more potent diastereomer was evaluated in vivo in experimentally induced Pseudomonas keratitis in rabbits. Following inoculation of one cornea of each rabbit, topical treatment with a 1 mM solution of the inhibitor significantly delayed the onset of corneal melting and perforation, as compared with the results for the control and gentamicin-treated groups. This protective effect suggests that the inhibitor may have a therapeutic application by delaying the progression of corneal destruction in Pseudomonas keratitis.
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PMID:Inhibition of Pseudomonas aeruginosa elastase and Pseudomonas keratitis using a thiol-based peptide. 212 41

We have succeeded in the isolation, culture and morphological characterization of Rana ridibunda stomach enteric plexuses. We have furthermore obtained intra and extracellular bioelectric recordings from the explants in culture. The culture medium used (Eagle MEM), the collagenase digestion and the general culture conditions followed are similar to those applied to mammal enteric plexus explant cultures. The most striking difference is that the solutions were diluted to 70% in order to maintain the osmolar conditions required by the amphibian cells. Acetylcholinesterase, osmium tetroxide-zinc iodide- and para-formaldehyde-induced fluorescence methods reveal similar morphological images from the perivascular fibre plexuses. The different cell types observed by phase contrast light microscopy from the myenteric explants in culture have been identified by comparison with those revealed by the acetylcholinesterase method. The prevailing neurons show piramidal somas; other neurons are bipolar with oval somas and a third type shows oval somas tightly aligned, following sinusoidal courses. The intra and extracellular bioelectric recordings from the explants in culture show that the culture conditions we have applied preserve the electrophysiological properties of the neuronal membranes. These preliminary recordings will allow us to undertake the synaptic characterization of the gastrointestinal neurotransmitters in frogs.
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PMID:Frog stomach enteric plexuses in culture: isolation, morphological characterization and bioelectrical recordings. 213 57

Latent human fibroblast collagenase (HFC) can be activated by a variety of seemingly disparate means. In addition to the well-characterized activation by trypsin and organomercurial compounds, the enzyme can be activated to various extents by surfactants such as sodium dodecyl sulfate, by chaotropic ions such as SCN-, by disulfide compounds such as oxidized glutathione, by sulfhydryl alkylating agents such as N-ethylmaleimide, and by oxidants such as NaOCl. The underlying basis for these activations is the modification, exposure, or proteolytic release of the Cys73 residue from its habitat in the latent enzyme where it is thought to be complexed to the active-site zinc atom. This residue is not accessible for reaction with small molar excesses of dithionitrobenzoate in native, latent HFC. However, on addition of EDTA, this residue becomes fully exposed and is quantitatively labeled. All modes of activation of latent HFC are believed to involve the dissociation of Cys73 from the active-site zinc atom and its replacement by water, with the concomitant exposure of the active site. This is thought to be the primary event that precedes the well-known autolytic cleavages that are observed following the appearance of collagenase activity. The dissociation of Cys73 from the zinc atom in the latent enzyme "switches" the role of the zinc from a noncatalytic to a catalytic one. This "cysteine switch" mechanism of regulation may be applicable to the entire collagenase gene family.
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PMID:Multiple modes of activation of latent human fibroblast collagenase: evidence for the role of a Cys73 active-site zinc complex in latency and a "cysteine switch" mechanism for activation. 215 97

Procollagenase of human polymorphonuclear leucocytes was purified to homogeneity using a rapid and reproducible method. The purification procedure included affinity chromatography on zinc chelate Sepharose, ion exchange chromatography on Q-Sepharose fast flow, followed by affinity chromatography on orange Sepharose and finally a gel-permeation step on Sephacryl S-300. It was shown by SDS/PAGE, under reducing conditions, that the latent collagenase of human polymorphonuclear leucocytes consists of a single polypeptide chain with an apparent relative molecular mass of 85,000. Upon deglycosylation by endoglycosidase F digestion, the apparent relative molecular mass of the procollagenase was reduced to 53,000 which is similar to that of the fibroblast enzyme, and indicates a close relationship between both enzymes. Sequence data were determined by direct automated Edman degradation of the purified polymorphonuclear leucocyte procollagenase. The complete sequence of the propeptide region (residue 1-120) was thereby established. The proteolytic activation of the polymorphonuclear leucocyte procollagenase by various enzymes was investigated by determining the N-terminal sequences of the intermediate and final activated forms. Activation by chymotrypsin and cathepsin G led to the active form (Mr 64,000) by cleaving 79 N-terminal residues from the proenzyme. Trypsin activates in a two-step process. Cleavage of 48 N-terminal residues led to a still latent Mr 70,000 species. The final active form (Mr 65,000) was obtained by splitting off 20 additional N-terminal residues.
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PMID:Characterization and activation of procollagenase from human polymorphonuclear leucocytes. N-terminal sequence determination of the proenzyme and various proteolytically activated forms. 215 79

We have identified and sequenced a cDNA encoding human neutrophil collagenase from a lambda gt11 cDNA library constructed from mRNA extracted from the peripheral leukocytes of a patient with chronic granulocytic leukemia. The library was screened with an oligonucleotide probe constructed from the putative zinc-binding region of fibroblast collagenase. Eleven positive clones were identified, of which the one bearing the largest insert (2.2 kilobases (kb)) was sequenced. From the nucleotide sequence of the 2.2-kb cDNA clone we have deduced a 467-amino acid sequence representing the entire coding sequence of the enzyme. The deduced protein was confirmed as neutrophil collagenase by conformity with the amino-terminal sequence analyses of three tryptic peptides of purified neutrophil collagenase. The cDNA clone hybridizes to a 3.3-kb mRNA present in RNA extracted from human bone marrow but did not hybridize with RNA isolated from U937 cells induced to differentiate with phorbol myristate acetate. Neutrophil collagenase was found to possess 57% identity with the deduced protein sequence for fibroblast collagenase with 72% chemical similarity. Certain regions of the molecule, including the putative zinc-binding region, are highly conserved. When compared with the published sequence for fibroblast collagenase, neutrophil collagenase contains four additional sites for glycosylation. Medium from COS-7 cells transfected with a pcDNA1 eucaryotic expression vector containing cDNA for neutrophil collagenase degraded type I collagen into the three-quarter, one-quarter fragments characteristic of mammalian interstitial collagenase activity. Thus, definitive evidence based on the cDNA sequence confirms the neutrophil collagenase is a distinct gene product and a member of the family of matrix metalloproteinases.
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PMID:Human neutrophil collagenase. A distinct gene product with homology to other matrix metalloproteinases. 216 2

The general applicability of the "cysteine-switch" activation mechanism to the members of the matrix metalloproteinase (MMP) gene family is examined here. All currently known members of the MMP gene family share the characteristic that they are synthesized in a latent, inactive, form. Recent evidence suggests that this latency in human fibroblast collagenase (HFC) is the result of formation of an intramolecular complex between the single cysteine residue in its propeptide domain and the essential zinc atom in the catalytic domain, a complex that blocks the active site. Latent HFC can be activated by multiple means, all of which effect the dissociation of the cysteine residue from the complex. This is referred to as the "cysteine-switch" mechanism of activation. The propeptide domain that contains the critical cysteine residue and the catalytic domain that contains the zinc-binding site are the only two domains common to all of the MMPs. The amino acid sequences surrounding both the critical cysteine residue and a region of the protein chains containing two of the putative histidine zinc-binding ligands are highly conserved in all of the MMPs. A survey of the literature shows that many of the individual MMPs can be activated by the multiple means observed for latent HFC. These observations support the view that the cysteine-switch mechanism is applicable to all members of this gene family. This mechanism is unprecedented in enzymology as far as we know and offers the opportunity for multiple modes of physiological activation of these important enzymes. Since conditions in different cells and tissues may match those necessary to effect one of these activation modes for a given MMP, this may offer metabolic flexibility in the control of MMP activation.
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PMID:The cysteine switch: a principle of regulation of metalloproteinase activity with potential applicability to the entire matrix metalloproteinase gene family. 216 89

To get a better understanding of the possible role of proteases in the pathogenesis of fungal keratitis, the extracellular proteases of a clinical isolate of Aspergillus flavus, from a severe case of keratitis, were identified and partially characterized. This strain, designated CU226/88, was grown with a variety of substrates as nitrogen sources, under conditions that would be expected to derepress the production of extracellular proteases. When grown on minimal medium with milk protein as a nitrogen source, the fungus appeared to produce primarily a metalloprotease, which has a zinc cofactor. When grown with insoluble collagen or elastin as a nitrogen source, a serine protease and cysteine protease, as well as the metalloprotease, are produced. Strain CU226/88 can grow with collagen, but not elastin, as the sole source of carbon as well as nitrogen. It is possible that the collagenase activity is a mediator of the severe corneal destruction caused by this isolate.
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PMID:Extracellular proteases of Aspergillus flavus. Fungal keratitis, proteases, and pathogenesis. 217 95

Analysis of the transforming growth factor alpha (TGF alpha) cDNA predicts that the mature TGF alpha polypeptide is cleaved from the extracellular domain of its precursor, which is an integral membrane protein. Furthermore, the cleavage sites for the release of this mitogen are compatible with the participation of an elastaselike protease. We have immunohistochemically localized TGF alpha to the vascular smooth muscle cells in the arterioles. To investigate whether polymorphonuclear (PMN) leukocytic elastase, a blood-borne protease, could process the cell surface TGF alpha, NR6 cells were transfected with the rat TGF alpha cDNA. The cDNA encoded the entire open reading frame, and its expression was under the control of the mouse metallothionein I promoter. A cloned transfectant, termed 1B2, synthesized the TGF alpha precursor in a zinc-inducible manner, and the precursor was localized to the cell surface. Western blot (immunoblot) analysis indicated that treatment of the zinc-induced 1B2 cells with either PMN leukocytic or pancreatic elastase resulted in the release of the mature TGF alpha polypeptide. The released TGF alpha was bioactive, as it was capable of both competing with epidermal growth factor for binding to its receptor and stimulating [3H]thymidine incorporation in the mitogenic assay. Formaldehyde fixation of the 1B2 cells eliminated basal release of TGF alpha but allowed normal processing by both PMN leukocytic and pancreatic elastase to occur. However, human cathepsin G, bovine pancreatic alpha 1-chymotrypsin, collagenase, trypsin, subtilisin, and plasmin failed to release any detectable fragments of the TGF alpha precursor from the fixed cells. The location of TGF alpha in the arterioles and ability of PMN leukocytic elastase to process the membrane-bound TGF alpha precursor suggests a novel role for this elastase at the wound site.
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PMID:Transforming growth factor alpha in arterioles: cell surface processing of its precursor by elastases. 220 95


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