The components of troponin from chicken fast skeletal muscle. A comparison of troponin T and troponin I from breast and leg muscle

Abstract

The 3 components of troponin were prepared from chicken breast and leg muscle. The troponin I and T components were separated by chromatography on DEAE-cellulose after citraconylation and without the use of urea-containing buffers. The troponin I and C components were similar to their counterparts from rabbit fast skeletal muscle, and a comparison of the troponin I components from breast and leg muscle by amino acid analysis, gel electrophoresis and peptide mapping provided strong evidence for the identity of these proteins. The MW of the troponin T components from breast and leg muscle were 33,500 and 30,500, respectively, determined by gel filtration. A comparison of these 2 proteins by methods similar to those used for the troponin I components suggested that they differed only in the N-terminal region of the sequence, the breast-muscle troponin T having an extra length of polypeptide chain of approximately 24 residues that was rich in histidine and alanine. The N-terminal hexapeptide sequence was the same in both proteins: (Ser,Asx,Glx)Thr-Glu-Glu. The genetic implications of these findings were considered.