Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.24.23 (MMP)
 4,246 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The action of three matrix metalloproteinases (MMPs), 72- and 95-kDa gelatinases (MMP-2 and MMP-9) and PUMP (MMP-7), and a cysteine proteinase, cathepsin B, were investigated on aggrecan the major proteoglycan of cartilage. All the enzymes cleaved aggrecan although the activity of the 95-kDa gelatinase was very low. Specific cleavage sites were investigated following incubation with a purified aggrecan G1-G2 domain fragment (150 kDa). Both gelatinases produced 110-kDa G2 and 56-kDa G1 products by a single cleavage at an Asn-Phe bond within the interglobular domain close to the G1 domain. This was similar to the action of stromelysin (MMP-3) (Fosang, A. J., Neame, P. J., Hardingham, T. E., Murphy, G., and Hamilton, J. A. (1991) J. Biol. Chem. 266, 15579-15582). Cathepsin B also produced two fragments from a single cleavage at a Gly-Val bond only three amino acids C-terminal to the metalloproteinase cleavage site. PUMP cleaved at the metalloproteinase Asn-Phe site, but in addition produced a low yield of a smaller G2 fragment (56 kDa) corresponding to cleavage between Asp441 and Leu442 (human sequence), within the interglobular domain, close to the G2 domain. The apparent difference in size between the two G2 fragments released by PUMP (110 and 56 kDa) was much greater than predicted from the peptide length between the cleavage sites (100 amino acids). However, keratanase digestion greatly reduced the size of the 110-kDa G2 fragment, while producing only a small reduction in size of the 56-kDa product, showing that there was approximately 30-40 kDa of keratan sulfate attached to the interglobular domain between the PUMP cleavage sites. This new structural information on aggrecan may account for the previously observed stiffness of the interglobular domains when viewed by rotary shadowing electron microscopy (Paulsson, M., Morgelin, M., Wiedemann, H., Beardmore-Gray, M., Dunham, D. G., Hardingham, T. E., Heinegard, D., Timpl, R., and Engel, J. (1987) Biochem. J. 245, 763-772). These results show that in spite of a high keratan sulfate content the interglobular domain provides important sites for cleavage by different proteinases, including several members of the matrix metalloproteinase family.
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PMID:The interglobular domain of cartilage aggrecan is cleaved by PUMP, gelatinases, and cathepsin B. 132 52

We have developed a monoclonal antibody AF-28 that specifically recognizes a neo-epitope on polypeptides with N-terminal FFGVG ... sequences. This sequence is found at the N-terminus of aggrecan fragments that have been digested with matrix metalloproteinases (MMPs). By immunoblotting, monoclonal antibody AF-28 specifically detected G2 fragments derived from an aggrecan G1-G2 substrate digested with stromelysin, collagenase, gelatinase and matrilysin, but failed to detect G2 fragments obtained from elastase, trypsin or cathepsin B digests. Undigested G1-G2 was not detected. In addition, AF-28 antibody detected fragments derived from whole aggrecan and this detection did not require prior treatment with chondroitinase or keratanase. Competition experiments confirmed that peptides containing internal ... FFGVG ... sequences were not detected by the antibody, while native MMP-digested aggrecan fragments and a synthetic 32-mer peptide with FFGVG ... N-termini were equally competitive on a molar basis. An FFGVG 5-mer, and an FGVGGEEDI9-mer which lacked the N-terminal phenylalanine residue, were 50 times and 230 times respectively less competitive than the FFGVG ... 32-mer. Two fragments from the interglobular domain, F342-F373 and F342-D441, that are predicted products of G1-G2 digestion by neutrophil collagenase but have not previously been detected, could be detected with AF-28. The epitope recognized by AF-28 was also detected in human synovial fluids by Western blot analysis. A broad band of 100-200 kDa was detected in some patients and a dominant band of 40-60 kDa was found in two patients. The size of this small fragment corresponds with that seen for the porcine F342-E373 product and may represent the natural physiological product of aggrecan cleaved in vivo at both the MMP site (... DIPEN341 decreases F342FGVG ...) and the aggrecanase site (... ITEGE373 decreases A374RGSVI ...).
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PMID:Development of a cleavage-site-specific monoclonal antibody for detecting metalloproteinase-derived aggrecan fragments: detection of fragments in human synovial fluids. 754 17