Evidence for the participation of two sperm proteases, spermosin and acrosin, in fertilization of the ascidian, Halocynthia roretzi: inhibitory effects of leupeptin analogs on enzyme activities and fertilization.
Ten kinds of argininal-containing compounds were examined for their inhibitory effects on the fertilization of the solitary ascidian and on the activities of acrosin and spermosin, trypsin-like proteases isolated from spermatozoa of this animal. Benzyloxycarbonyl-Val-Pro-argininal (I) and benzyloxycarbonyl-Phe-Leu-argininal (II) showed the strongest inhibition on the fertilization. Leupeptin (acetyl-Leu-Leu-argininal, III) was ranked next (I, II greater than III). The activity of ascidian acrosin was susceptible to most of the compounds, among which II was the best inhibitor and followed with I and III (II greater than I, III). Spermosin suffered significant inhibition only with I and II (I greater than II). These results suggest that not only acrosin but also spermosin is involved in fertilization of the ascidian.
D000176:Acrosin / Q000037:antagonists & inhibitors*; D000818:Animals; D005260:Female; D005306:Fertilization / Q000187:drug effects*; D007700:Kinetics; D007976:Leupeptins / Q000494:pharmacology*; D008297:Male; D009842:Oligopeptides / Q000494:pharmacology*; D011480:Protease Inhibitors; D012697:Serine Endopeptidases; D013094:Spermatozoa / Q000187:drug effects / Q000201:enzymology / Q000502:physiology*; D013329:Structure-Activity Relationship; D014561:Urochordata / Q000502:physiology
D007976:Leupeptins; D009842:Oligopeptides; D011480:Protease Inhibitors; D012697:Serine Endopeptidases; C040779:spermosin; D000176:Acrosin