Characterization of Capacitation Inhibitory Protein from Rabbit Seminal Plasma : Homology with Human Annexins

Abstract

A protein was purified from rabbit seminal plasma using preparative acrylamide disc electrophoresis, ammonium sulfate precipitation and gel filtration. The protein inhibited the in vitro fertilization of mouse ova inseminated with epididymal sperm and with capacitated sperm. The inhibition was not observed, however, when only ova were exposed to the protein prior to mixing with sperm. The partial protein sequence analysis revealed the strong homology of the rabbit fertilization inhibitory protein to human annexin V.