“…The expression of Izumo was found to be testisspecific and was not detectable on the surface of fresh sperm but only became apparent after initiation of the acrosome reaction (Rubinstein et al, 2006) In addition, a number of enzymes mediating the process of spermatogenesis have also been discovered. The Testis Specific Serine Kinases (TSSKs) are a collection of kinases in germ cells or in testis, which include TSSK1, TSSK2, TSSK3 and others (Bielke et al, 1994;Blaschke et al, 1994;Kueng et al, 1997;Zuercher et al, 2000). Since Specific Serine Kinases are only synthesized postmeiotically in spermatogenesis, they were proposed to act during sperm maturation, capacitation and fertilization.…”