Myosin isoenzymes of amphibian hearts.

Cardiac myosins of 10 amphibian species were analysed by electrophoresis. Depending on the species, ventricles and atria contained one or two isomyosins. There were components similar to V2 or V1 of the rat and migrating faster. In the same heart, ventricular and atrial isomyosins were similar or tissue specific. It is suggested that the presence of multiple molecular forms of myosin in the heart is a common property of all vertebrates.