Structural Differences of Myosin Heavy Chains in Normal and Denervated Muscles

The pectoral nerve of an adult chicken was ligated and cut, and six months later the resulting atrophied pectoral muscle was taken out. Subfragment-2 (S-2) of myosin prepared from the denervated and atrophied muscle was obtained by successive digestions in physiological and higher ionic strength buffers with α-chymotrypsin, and purified by gel chromatography on a Sephacryl S-300 column after S-carboxymethylation. The S-2 was digested with lysylenopeptidase, and 11 peptides were isolated by reverse-phase high performance liquid chlomatoglaphy. Their sequences determined by using an automated protein sequencer were compared with the primary structure of myosin heavy chain normally expressed in the pectoral muscle. The results clarified that at least two kinds of different myosin heavy chains from normal one were expressed in the atrophied muscle