Primary structure of rabbit skeletal muscle troponin-T. Purification of cyanogen bromide fragments and the amino acid sequence of fragment CB2.

Troponin-T was cleaved by cyanogen bromide (CB) to produce the seven fragments CB1 (151 residues), CB3 (70 residues), CB2 (81 residues), CB5 (24 residues), CB4 (54 residues), CB7 (8 residues), and CB6 (21 residues). The NH2-terminal fragment CB1, composed of CB3 plus CB2, had an internal homoserine which was not completely cleaved. The amino acid sequence of CB2 was determined by a combination of automated and manual Edman degradation techniques. Peptides suitable for the latter method were derived from tryptic, alpha-chymotryptic, alpha-lytic protease, and thermolytic digestions. Fragment CB2 contains 81 of the 259 residues of troponin-T.