Could enhance the fertilizing capacity of bull spermatozoa upon interaction with heparin-like glycosaminoglycans present in the female genital tract. Exhibits both simulatory and inhibitory actions on the release of pituitary gonadotropins. Homodimer. Major component of seminal plasma. O-linked glycan consists of Gal-GalNAc disaccharide which is modified with a sialic acid residue (macro- and/or microheterogeneity account for differences between BSP-A1 and BSP-A2). Belongs to the seminal plasma protein family.