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Proteasome (multicatalytic proteinase) of sea urchin sperm and its possible participation in the acrosome reaction
Author(s) -
Matsumura Kiyotaka,
Aketa Kenji
Publication year - 1991
Publication title -
molecular reproduction and development
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.745
H-Index - 105
eISSN - 1098-2795
pISSN - 1040-452X
DOI - 10.1002/mrd.1080290215
Subject(s) - biology , protease , acrosome reaction , acrosin , biochemistry , chymotrypsin , proteases , trypsin , gel electrophoresis , polyacrylamide gel electrophoresis , sea urchin , size exclusion chromatography , acrosome , sperm , enzyme , sodium dodecyl sulfate , microbiology and biotechnology , in vitro , botany
The egg jelly‐induced acrosome reaction of the sea urchin, Strongylocentrotus intermedius , was inhibited by succinyl‐Leu‐Leu‐Val‐Tyr‐4‐methylcoumaryl‐7‐amide (Suc‐Leu‐Leu‐Val‐Tyr‐MCA), but not by Suc‐Ala‐Ala‐Pro‐Phe‐MCA. The proteases with hydrolytic activity toward the former were purified from sperm extract by DEAE‐Sephacel and hydroxylapatite chromatographies, Sephacryl S‐300 gel filtration, and heparin‐Sepharose CL‐6B chromatography. Two types of protease were separated, and the molecular weights were estimated to be 65 and 700 kDa, respectively, by gel filtration. The former was accompanied by hydrolytic activity toward Suc‐Ala‐Ala‐Pro‐Phe‐MCA, which was not hydrolyzed by the latter. Polyacrylamide gel electrophoresis of 700 kDa protease gave a single protein band under nondenaturing conditions and at least eight bands in the range of 22–33 kDa in the presence of sodium dodecyl sulfate (SDS). The substrate specificity and the inhibitor sensitivity of 700 kDa protease indicate that it contains two types of the activity, one is chymotrypsin‐type and the other trypsin‐type. The former activity was enhanced by poly‐L‐lysine or SDS. These properties of 700 kDa protease are similar to those of proteasomes (multicatalytic proteinases) isolated from various eukaryotic sources. We had previously shown that inhibitors of chymotrypsin‐like proteases inhibit the increase of intracellular Ca 2+ concentration by egg jelly, resulting in the inhibition of the acrosome reaction of St. intermedius (Matsumura and Aketa, Gamete Res 23:255–266, 1989). Bringing these findings together, we suggest that the chymotrypsin‐like activity of sperm proteasome participates in the onset of the acrosome reaction of St. intermedius .