ABSTRACT

We have purified proteasomes form spermatozoa and eggs of sea urchins by successive chromatographies on DEAE-cellulose, hydroxylapatite, and Sepharose 6B. Each of the purified proteasomes seems to exist in a large molecular form (molecular weight, 630,000), as revealed by gel filtration. They gave several bands on SDS-polyacrylamide gel electrophoresis. They show, at least, three different kinds of protease activities, chymotrypsin-like, trypsin-like, and V-8 protease-like activities with different pH optima and inhibitor-susceptibilities. Three enzyme activities are stimulated by a low concentration of sodium lauryl sulfate. Immunoblot analyses using antibodies raised against sperm and egg proteasomes indicate that a little difference in composition of protein components exists between the two proteasomes.