**Phosphorylation/dephosphorylation of tyrosine residues:**

Two protein bands (76TyD and 57TyD of figure 7A) which in fresh sperm were completely dephosphorylated after motility initiation, in frozen– thawed remained phosphorylated (Fig. 9A), while the cluster of proteins of 15-9 TyP (Fig. 7A), that were phosphorylated when fresh sperm shifted from the immotile to the motile phase, were much less phosphorylated in frozen–thawed activated sperm (Fig. 9A).
