PMID: 7016857Jun 10, 1981Paper

Boar acrosin. Association of an endogenous membrane proteinase with phospholipid membranes.

The Journal of Biological Chemistry
J W StrausK L Polakoski

Abstract

Acrosin, an enzyme required for fertilization, is an endogenous proteinase associated with membranes of the sperm acrosome. Liposomes were utilized as a model system to evaluate the mode of association between highly purified boar acrosin and phospholipid bilayer membranes. Acrosin was observed to bind to liposomes containing acidic phospholipids such as phosphatidylglycerol, cardiolipin, and phosphatidylserine. There was no apparent binding of acrosin to liposomes which consisted of nonacidic phospholipids, thus indicating that an ionic phospholipid constituent was required for binding. Increased ionic strength caused a significant reduction in acrosin-liposome association with an inverse effect on enzyme-membrane dissociation. Acrosin-liposome association and dissociation were similarly effected by increasing concentrations of divalent cations at constant ionic strength, and by reductions in pH. Equilibrium binding experiments, with anionic liposomes, suggest the presence of either multiple classes of independent binding sites, or apparent negative cooperativity, with a range in the apparent affinity constant (Ka) from 2 x 10(11) M-1 at low acrosin concentrations to 3 x 10(8) M-1 at high acrosin concentrations. The membrane-a...Continue Reading

Related Concepts

Related Feeds

ASBMB Publications

The American Society for Biochemistry and Molecular Biology (ASBMB) includes the Journal of Biological Chemistry, Molecular & Cellular Proteomics, and the Journal of Lipid Research. Discover the latest research from ASBMB here.

© 2021 Meta ULC. All rights reserved