The amino acid sequence and phosphorylation sites of a boar transition protein 1

Boar transition protein 1 was extracted with acid from the testes, purified by chromatographies on CM-Sephadex C-25 and Sephadex G-50, and reduced and carboxymethylated. The modified protein was purified by HPLC on Nucleosil 300 7C18. The primary structure of the protein was determined by automated Edman degradation of the C-terminal peptide of the BrCN-cleaved protein and of the whole protein, and by carboxypeptidase digestion of it. The study of phosphorylation sites showed that Ser36 and Ser39 in the very conserved sequence 29-42 were partly phosphorylated, suggesting the involvement of this region in the interaction with DNA.