title: A Zn2+-dependent and histone H1-specific protease in sea urchin sperm.
abstract: Protease activity was extracted from sea urchin sperm with 1% Triton X-100 and partially purified by DEAE-cellulose and Sephadex G-100 chromatography. The enzyme preferentially degraded histone H1, while showing only a weak activity toward other histones. Heat-denatured casein and bovine serum albumin were not digested by this enzyme under the present experimental conditions. This protease hydrolyzed only Boc-Val-Leu-Lys-MCA among various peptidyl-MCAs. The optimal pH ranged from 7 to 11. Its molecular weight was about 41,000. Among various known inhibitors of proteases, only omicron-phenanthroline effectively inhibited the activity. The enzyme was stimulated by Zn2+ or Co2+. It was inactivated by omicron-phenanthroline but could be reactivated by the addition of Zn2+ or Co2+. Therefore, this protease seems to be a metalloprotease dependent on Zn2+ or Co2+. The insensitivity of this enzyme to phosphoramidon and its very restricted substrate specificity suggest that this enzyme is very different from other metalloproteases described hitherto.
mesh_terms: D000818:Animals; D003035:Cobalt / Q000494:pharmacology; D006657:Histones / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D008297:Male; D008970:Molecular Weight; D010447:Peptide Hydrolases / Q000302:isolation & purification*; D011480:Protease Inhibitors / Q000494:pharmacology; D012617:Sea Urchins; D013094:Spermatozoa / Q000201:enzymology*; D013379:Substrate Specificity; D013696:Temperature; D015032:Zinc / Q000494:pharmacology*
chemical_list: D006657:Histones; D011480:Protease Inhibitors; D003035:Cobalt; D010447:Peptide Hydrolases; D015032:Zinc