Preferential inhibition of 72- and 92-kDa gelatinases by tissue inhibitor of metalloproteinases-2.
Transformed human fibroblasts secrete two structurally and functionally related inhibitors of matrix metalloproteinases, tissue inhibitor of metalloproteinases (TIMP) 1 and 2. In assays measuring the relative inhibitory capability of TIMP-1 and TIMP-2 against autoactivated 72-kDa gelatinase, which consists of two major active peptides and several inactive fragments, TIMP-2 was more effective than TIMP-1. The isolated 42.5-kDa active fragment that formed as a result of the autoactivation of 72-kDa gelatinase showed the greatest preference for TIMP-2; at half-maximal inhibition, TIMP-2 was greater than 10-fold more effective than TIMP-1. TIMP-2 was also greater than 2-fold more effective than TIMP-1 at inhibiting 72-kDa gelatinase-TIMP-2 complexes activated with 4-aminophenylmercuric acetate, and greater than 7-fold more effective than TIMP-1 at inhibiting 92-kDa gelatinase activated with 4-aminophenylmercuric acetate. Furthermore, these active gelatinases preferentially bound 125I-TIMP-2 when incubated with equal amounts of radiolabeled TIMP-1 and TIMP-2. The ratios of 125I-TIMP-2/125I-TIMP-1 binding to 92-kDa gelatinase, autoactivated 72-kDa gelatinase, and 42.5-kDa fragment were 4.4, 10, and 33, respectively. On the other hand, interstitial collagenase was inhibited by TIMP-1 greater than 2-fold more effectively than TIMP-2 in assays measuring cleavage of loose collagen fibrils.
Howard
E W
EW
Laboratory of Radiobiology and Environmental Health, University of California, San Francisco 94143-0750.
Bullen
E C
EC
Banda
M J
MJ
D002460:Cell Line; D004789:Enzyme Activation; D004792:Enzyme Precursors / Q000302:isolation & purification; D018093:Gelatinases; D006023:Glycoproteins / Q000302:isolation & purification / Q000494:pharmacology; D006801:Humans; D007700:Kinetics; D008666:Metalloendopeptidases / Q000037:antagonists & inhibitors*; D008970:Molecular Weight; D009363:Neoplasm Proteins / Q000378:metabolism / Q000494:pharmacology*; D010434:Pepsin A / Q000037:antagonists & inhibitors* / Q000302:isolation & purification; D011485:Protein Binding; D019716:Tissue Inhibitor of Metalloproteinase-2; D019714:Tissue Inhibitor of Metalloproteinases
D004792:Enzyme Precursors; D006023:Glycoproteins; D009363:Neoplasm Proteins; D019714:Tissue Inhibitor of Metalloproteinases; D019716:Tissue Inhibitor of Metalloproteinase-2; D010434:Pepsin A; D018093:Gelatinases; D008666:Metalloendopeptidases; C069860:progelatinase