TRANSFER OF AMINOPEPTIDASE ACTIVITY FROM PROSTASOMES TO SPERM

Prostasomes are membranous vesicles (150-200 nm diameter) present in h uman semen. They are secreted by the prostate and contain large amount s of cholesterol, sphingomyelin and Ca2+. In addition, some of their p roteins are enzymes. Prostasomes enhance the motility of ejaculated sp ermatozoa and are involved in a number of additional biological functi ons. It has been demonstrated that lipid can be transferred from prost asomes to sperm by a fusion process occurring at slightly acidic pH. I n this paper, we show that an aminopeptidase activity is transferred f rom prostasome to sperm. This may be of particular interest since it i ndicates the involvement of protein in the process of fusion and becau se sperm may acquire new membrane-bound proteins by this procedure. (C ) 1997 Elsevier Science B.V.