Selective binding of specific rat epididymal secretory proteins to spermatozoa and erythrocytes

Abstract

Abstract Tissue pieces from the caput epididymidis of the rat were incubated in vitro with ( 35 S) methionine to produce radioactive secretory proteins. The radioactive secretory proteins so formed were tested for their ability to bind to washed rat spermatozoa collected from the rete testis and cauda epididymidis, and to rat erythrocytes. The sperm and erythrocytes bound approximately 5% of the total radioactive protein. Binding was protein‐specific in that only selected proteins became associated with the cells. Binding was not cell‐specific, however, since testicular spermatozoa, caudal spermatozoa, and erythrocytes all bound the same proteins to a similar degree.