Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.5.1.52 (PNGase F)
 1,527 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A Mr 95,000 matrix metalloproteinase (MMP) produced by rat mammary carcinoma cells has been isolated and characterized. The MMP was secreted in a proteolytically inactive form that was free from bound tissue inhibitor of metalloproteinases. The enzyme was highly glycosylated as evident from an apparent drop of Mr from 95,000 to 83,000 after treatment with N-glycanase. Rotary shadowing electron micrographs of purified proenzyme preparations revealed a uniform set of ellipsoidal molecules. Treatment of the proenzyme with 1% SDS resulted in generation of catalytic activity and exposed a cryptic unpaired Cys residue. The latent proenzyme may be activated in at least three additional ways: either spontaneously upon storage, by treatment with organomercurials, or by limited proteolysis by trypsin. Each mode of activation yielded a distinct pattern of cleavage of the enzyme. The activated enzyme cleaved gelatin (denatured type I collagen) and native type IV and V collagen at 30-37 degrees C. Noncollagenous proteins including alpha 1-proteinase inhibitor, casein, and fibrinogen also were cleaved. The rat mammary carcinoma cell line that produces the Mr 95,000 MMP is composed of two distinct (epithelial- and myoepithelial-like) cell types. The enzyme is expressed constitutively by the epithelial cells. This suggests that expression of the Mr 95,000 MMP is regulated differently from that of interstitial collagenase, which is produced by the epithelial cells only in response to specific inductive factor(s) from the myoepithelial-like cells. Monoclonal antibodies raised against the purified latent Mr 95,000 form of the enzyme bind specifically to the Mr 95,000 MMP and have been used to localize the enzyme to the Golgi region and cytoplasmic granules of the epithelial cells.
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PMID:Characteristics of a 95-kDa matrix metalloproteinase produced by mammary carcinoma cells. 199 64

Two members of the matrix metalloproteinase (MMP)1 family of enzymes are expressed at elevated levels in highly aggressive human tumor cells and have been implicated in the catalytic functions of extracellular proteolysis. The zymogen forms of these enzymes are designated proMMP-2 and proMMP-9, also known as 72kDa and 92kDa type IV collagenases/gelatinases, respectively. The MMP family of enzymes can be activated in vitro by a number of compounds including the organomercurial 4-aminophenylmercuric acetate (APMA). The natural or in vivo activators of MMP-2 and MMP-9 are at present unknown. A partially purified preparation of MMP-9 was used to immunize mice for the isolation of monoclonal antibodies (mAbs). Three IgG1 mAbs were identified by immunoreactivity with purified MMP-9 and are designated 6-6B, 7-11C, and 8-3H. These mAbs react specifically with MMP-9 by ELISA and Western blot. Additionally, these mAbs react with N-glycanase treated 92kDa protein. These mAbs were tested for their ability to inhibit enzyme activation in a radio-labeled gelatin assay. The 6-6B mAb inhibited the activation of MMP-9, but had no effect on MMP-2. These mAbs are highly specific to human MMP-9 and the 6-6B mAb will be extremely useful for examining the autolytic and catalytic activity of MMP-9 in normal and abnormal biological processes.
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PMID:Inhibition of matrix metalloproteinase 9 activation by a specific monoclonal antibody. 824 15

Staphylococcal superantigen-like proteins (SSL) show no superantigenic activity but have recently been considered to act as immune suppressors. It was previously reported that SSL5 bound to P-selectin glycoprotein ligand-1 (PSGL-1) and matrix metalloproteinase (MMP)-9, leading to inhibition of leukocyte adhesion and invasion. These interactions were suggested to depend on sialic acid-containing glycans of MMP-9, but the roles of sialic acids in the interaction between SSL5 and MMP-9 are still controversial. In the present study, we prepared recombinant glutathione S-transferase-tagged SSL5 (GST-SSL5) and analyzed its binding capacity to MMP-9 by pull-down assay after various modifications of its carbohydrate moieties. We observed that GST-SSL5 specifically bound to MMP-9 from a human monocytic leukemia cell line (THP-1 cells) and inhibited its enzymatic activity in a concentration-dependent manner. After MMP-9 was treated with neuraminidase, its binding activity towards GST-SSL5 was markedly decreased. Furthermore, recombinant MMP-9 produced by sialic acid-deficient Lec2 mutant cells showed much lower affinity for SSL5 than that produced by wild-type CHO-K1 cells. Treatment of MMP-9 with PNGase F to remove N-glycan resulted in no significant change in the GST-SSL5/MMP-9 interaction. In contrast, the binding of GST-SSL5 to MMP-9 secreted from THP-1 cells cultured in the presence of an inhibitor for the biosynthesis of O-glycan (benzyl-GalNAc) was weaker than the binding of GST-SSL5 to MMP-9 secreted from untreated cells. These results strongly suggest the importance of the sialic acid-containing O-glycans of MMP-9 for the interaction of MMP-9 with GST-SSL5.
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PMID:Role of sialic acid-containing glycans of matrix metalloproteinase-9 (MMP-9) in the interaction between MMP-9 and staphylococcal superantigen-like protein 5. 2932 25