Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.24.35 (matrix metalloproteinase 9)
 2,207 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The precursor of matrix metalloproteinase 9 (proMMP-9), also known as '92 kDa progelatinase/type IV procollagenase', was purified from the conditioned medium of U937 monocytic leukaemia and HT1080 fibrosarcoma cell lines stimulated with phorbol 12-myristate 13-acetate. ProMMP-9 in these culture media is non-covalently complexed with the 29 kDa tissue inhibitor of metalloproteinases (TIMP), but free proMMP-9 was separated from the TIMP-proMMP-9 complex by chromatography on Green A Dyematrex gel. The final product was homogeneous on SDS/PAGE, with a molecular mass of 88 kDa without reduction and 92 kDa with reduction. Treatment of proMMP-9 with 4-aminophenylmercuric acetate converted the 88 kDa precursor into 80 kDa and 68 kDa forms. Gelatin-containing zymographic analysis showed zones of lysis associated with all three species. However, only the 68 kDa species was shown to be catalytically active by its ability to bind to alpha 2-macroglobulin. In the presence of an equimolar amount of TIMP, only the 80 kDa species was generated by treatment with 4-aminophenylmercuric acetate, but no enzyme activity was detected. This indicates that TIMP binds to the 80 kDa intermediate and inhibits the generation of the active 68 kDa species. Eight endopeptidases (trypsin, chymotrypsin, plasmin, plasma kallikrein, thrombin, cathepsin G, neutrophil elastase and thermolysin) were tested for their ability to activate proMMP-9. Of them, trypsin was the most effective activator of proMMP-9. Only partial activation (10-30%) was observed with plasmin, cathepsin G and chymotrypsin. The active forms generated by trypsin were identified as 80 kDa, 74 kDa and 66 kDa by their abilities to bind to alpha 2-macroglobulin. In the presence of an equimolar amount of TIMP, proMMP-9 was also converted into the same molecular-mass species by trypsin, but they were not proteolytically active. This suggests activated MMP-9 is inhibited by TIMP. Activated MMP-9 digested gelatin, type-V collagen, reduced carboxymethylated transferrin and, to a lesser extent, type-IV collagen and laminin A chain. The specific activity against gelatin was estimated to be 15,000 units/mg (1 unit = 1 microgram of gelatin degraded/min at 37 degrees C) by titration with alpha 2-macroglobulin. Comparative studies on digestion of gelatin and collagen types IV and V by MMP-9 and MMP-2 indicated that both enzymes degrade these substrates into similar fragments. However, the susceptibilities of laminin, fibronectin and reduced carboxymethylated transferrin to these two MMPs were sufficiently different to indicate differences in substrate specificities between these two closely related proteinases.
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PMID:Purification and characterization of matrix metalloproteinase 9 from U937 monocytic leukaemia and HT1080 fibrosarcoma cells. 137 48

The precursor of matrix metalloproteinase 9 (pro-MMP-9) forms a complex with the tissue inhibitor of metalloproteinases (TIMP)-1 through the C-terminal domain of each molecule, and the N-terminal domain of TIMP-1 in the complex interacts and inhibits active MMPs. We have reported that a catalytic amount of MMP-3 (stromelysin 1) activates pro-MMP-9 (Ogata, Y., Enghild, J. J., and Nagase, H. (1992) J. Biol. Chem. 267, 3581-3584). To activate pro-MMP-9 in the complex, however, an excess molar amount of MMP-3 is required to saturate the TIMP-1 in the complex. The aim of this study was to test the hypothesis that the requirement for excess MMP-3 can be circumvented by specific destruction of TIMP-1 by non-target proteinases. We have tested trypsin, plasmin, cathepsin G, neutrophil elastase, and chymotrypsin as possible inactivators of TIMP-1 and found that neutrophil elastase inactivates TIMP-1 in the complex without significant destruction of pro-MMP-9. Once TIMP-1 is inactivated, pro-MMP-9 can be readily activated by a catalytic amount of MMP-3. These results suggest that neutrophil elastase may participate in the connective tissue destruction at the inflammatory sites not only by its direct action on matrix macromolecules but also by rendering pro-MMP-9 in the pro-MMP-9.TIMP-1 complex activable by MMP-3 as well as activating pro-MMP-3.
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PMID:Preferential inactivation of tissue inhibitor of metalloproteinases-1 that is bound to the precursor of matrix metalloproteinase 9 (progelatinase B) by human neutrophil elastase. 762 55

The assay for the cross-linked carboxyterminal telopeptide of type I collagen (ICTP) has been shown to reflect increased type I collagen degradation in such pathological conditions as bone metastases and rheumatoid arthritis, but to be rather insensitive to the changes in physiological bone collagen turnover (e.g., induced by estrogen or bisphosphonate treatment). To determine the reasons for this discrepancy we localized the antigenic determinant recognized by the ICTP assay and studied the effects of two major osteoclastic proteinases, cathepsin K (EC 3.4.22.38) and matrix metalloproteinase-9 (MMP-9; gelatinase B; EC 3.4.24.35), on immunoreactivity. The antigenic determinant was shown to reside within the hydrophobic phenylalanine-rich regions of the carboxyterminal telopeptides of the two alpha1 chains of human type I collagen, situated between the triple helical domain and the lysine-derived trivalent cross-link. This conclusion was based on differences between the amino acid sequences and cross reactivities of the corresponding human and bovine antigens before and after proteolytic treatments with chymotrypsin. A trivalent cross-link is necessary for providing such a structure, because the divalently cross-linked and monomeric natural and synthetic peptides from the same region, but containing only one phenylalanine-rich sequence, showed poor immunoreaction. Recombinant human cathepsin K cleaved the trivalently cross-linked ICTP structure at two sites between the phenylalanine-rich region and the cross-link, destroying the reactivity with ICTP antibodies. On the contrary, the treatment of isolated ICTP by the matrix metalloproteinases MMP-9 (gelatinase B), MMP-1 (collagenase 1), or MMP-13 (collagenase 3) had no effect on the immunoreaction. Our results indicate that the increased circulating concentrations of ICTP found in several clinical situations are most likely produced by matrix metalloproteinases, whereas cathepsin K-mediated, osteoclastic bone resorption destroys ICTP antigenicity.
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PMID:Immunochemical characterization of assay for carboxyterminal telopeptide of human type I collagen: loss of antigenicity by treatment with cathepsin K. 1071 80