Sequence Determination of Amino- and Carboxyl-Terminal Residues of Hypocalcemic Profein TP₁ extracted from Bovine Thymus Gland

Abstract

End group amino acid sequence was determined on a hypocalcemic protein TP₁ purified from bovine thymus gland. Amino-terminal amino acid sequence was deduced to be His-Asx-Ala-Glx- by the dansyl-Edman degradation method. Carboxyl-terminal amino acid sequence was analyzed by digestion with carboxypeptidase A and Y, and it was deduced to be-Thr-Ala-Lys. Furthermore, the carboxyl-terminal amino acid was confirmed to be lysine alone by the hydrazinolysis method. According to these results and from previous data, it became apparent that TP₁ did not bear the subunit structure, and it was clearly different from other hypocalcemic proteins obtained from bovine thymus and parotid gland.