An alkaline metallo-proteinase in the human uterine cervix and changes in its activity by cervical ripening

Abstract

Human uterine cervix at term pregnancy was found to contain an alkaline metallo-proteinase by use of a synthetic substrate, 2,4-dinitrophenyl- l-Pro- l-Gln-Gly- l-Ile- l-Ala-Gly- l-Gln- d-Arg. The enzyme (with a molecular weight of 3.8 · 10 4) was most active around pH 9.2 toward casein and Nα- benzoyl- dl-Arg -p- nitroanilide . [ 14C]-Gelatin and proteoglycan subunit were also substrates for the enzyme, but [ 14C]collagen was not. In particular, the enzyme digested gelatin 70-times faster than the novel neutral proteinase in the cervix. Although EDTA was a potent inhibitor, 1,10-phenanthroline, human serum, diisopropylfluorophosphate and elastatinal had no effect on the enzyme. Alkaline proteinase in term pregnant cervices was significantly higher than in non-pregnant ones.