Cyclic AMP Induced Incorporation of 33Pi into Human Spermatozoa Membrane Components

Abstract

Three protein components of human spermatozoa membranes served as substrates for protein kinases. Protein III ("-'50,000 M W) was phosphorylated only under stimulation by exogenous cyclic-AMP, while protein II ( 80,000 It may also be suggested that modifications of the tertiary and quatennary structure of the plasma membrane proteins, through cyclic-AMP stimulated phosphorylation, may be requirements for the initial steps of capacitation.