PRESENCE OF FOLLIPSIN COMPLEXED WITH ALPHA(2)-MACROGLOBULIN IN PORCINE OVARIAN FOLLICULAR-FLUID

Using the follicular fluid of porcine ovaries as a source, a high-mole cular-weight protein having enzyme activity toward yloxycarbonyl-Gln-A rg-Arg-4-methylcoumaryl-7-amide was purified to an apparent homogeneit y. Its molecular weight was estimated to be approximately 720,000. The protein was immunoprecipitated with antihuman alpha(2)-macroglobulin antibody and was visualized in Western blot analysis using the same an tibody. Using Western blot analysis, an 85kDa polypeptide, which was r ecognized by antiporcine follipsin antibodies, was detected in this hi gh-molecular-weight protein. When tested for substrates and inhibitors with low molecular weight, the protein showed substrate specificity a nd an inhibitor profile similar to those of follipsin. On the basis of these results, it was concluded that the protein is a complex of foll ipsin with alpha(2)-macroglobulin. The complexed enzyme activated a si ngle-chain precursor tissue-type plasminogen activator at a drasticall y reduced rate compared with free follipsin. The present results sugge st that intrafollicular follipsin activity is regulated by the protein ase inhibitor alpha(2)-macroglobulin. (C) 1998 Wiley-Liss, Inc.