text: …to ions (Visconti et al., 2002), acquisition of hyperactivated motility (de Lamirande et al., 1997), and phosphorylation of proteins on tyrosine (Tyr), serine (Ser) and threonine (Thr) residues (de Lamirande et al., 1997; Baldi et al., 2000; de Lamirande and Gagnon 2002; Urner and Sakkas, 2003).