Isolation and characterization of tissue inhibitors of metalloproteinases (TIMP‐1 and TIMP‐2) from human rheumatoid synovial fluid

Abstract

The tissue inhibitors of metalloproteinases TIMP‐1 and TIMP‐2 were purified to apparent homogeneity from human rheumatoid synovial fluid (HRSF). The inhibitors were isolated by dissociation of non‐covalent gelatinase/TIMP complexes. TIMP‐1 migrated as a single polypeptide with M _r 28 500 on SDS‐PAGE, while the M _r of TIMP‐2 was 21 000. The inhibitory activity was stable under heat and acid pH. N‐terminal sequence data were obtained for the first 15 residues of both inhibitors and showed identity to the human fibroblast inhibitors TIMP‐1 and TIMP‐2. This is the first demonstration that TIMP‐1 and TIMP‐2 can be directly purified from human rheumatoid synovial fluid. The complex formation between the metalloproteinase inhibitors and leucocyte metalloproteinases was shown by immunoblotting.