Isomyosin redistribution in chronic pressure overload: comparison between peptide mapping and electrophoresis under non-denaturing conditions

Chronic pressure overload induces a redistribution in myosin isoenzymes as demonstrated by Ca++-activated ATPase activity, electrophoresis under non-denaturing conditions and immunohistochemistry. We compared, in two groups of renal hypertensive rats and control rats, the isoenzymic patterns obtained by electrophoresis under non-denaturing conditions with those observed after heavy chains digestion with S. Aureus V8 protease. In the hypertensive animals in which a shift towards the "slow" V2 and V3 isomyosins was evident, peptide mapping always gave origin to a band which was not present in the controls. Since we consider this peptide as a marker of the redistribution towards the "slow" isoforms, peptide mapping according to Cleveland appears to be a simple and useful method to assess differences in isomyosin composition, at least between hypertrophic pressure-overloaded and normal rat ventricles. Moreover, in our experience this technique is simple, the patterns obtained from highly p...