The ability of some epididymal proteins to associate with spermatozoa suggests their role in sperm maturation and/or in consequential phases of the fertilization process. By size exclusion chromatography, RP HPLC and SDS-PAGE we separated proteins from boar epididymal fluid. By the zymography method, we detected serine- and metallo-proteinases. Epididymal fluid proteins were tested with biotinylated glycoproteins of zona pellucida (ZP), hyaluronic acid, and heparin on nitrocellulose membrane after Western blot. The affinity of some epididymal proteins with heparin and hyaluronic acid suggests their role in sperm capacitation in the oviduct. Protein bands interacted with ZP glycoproteins on the blot. This phenomenon might indicate a possible role of epididymal fluid proteins bound to the sperm surface in epididymal maturation and in the sperm-egg binding
