Menschliches Calcitonin I. Isolierung und Charakterisierung

Abstract

Abstract Two highly active calcitonin peptides, M with 32 amino acids, and D a dimer of M, were isolated from a large human mediastinal C cell tumour. D can easily be transformed into M by the action of 1N ammonia; D and M afford two different sulphoxides, but all four peptides yield the same product upon oxidation with performic acid. Both D and M have a potency of about 120 MRC units/mg dry weight; their sulphoxides, by contrast, are almost inactive. Tryptic digestion of M produces an N‐terminal octadecapeptide (Tr I ) and a C‐terminal tetradecapeptide (Tr II ), the latter being also obtained from D. Amino acid analysis and other analytical data are presented. The structure of the human calcitonin peptides D and M is thus very different from that of porcine α‐thyrocalcitonin.