Specificity:Especially useful in discrimination of morphologically altered "round-headed" spermatozoa. Polypeptide(s) Reacting: Bovine cylicin I (Mr 74.788, deduced from sequence analysis), a basic protein (IEP 10.55) of the sperm head cytoskeleton with Mr 58,000 on SDS-PAGE; Multiple band proteins with MW 58, 63, 69 and 74kD of calyx-associated polypeptides of bovine spermatozoa. Species Crossreactivity: Human and bovine.