Myosin isoforms and their light chains from the ventricular muscle of the urodelan amphibian Pleurodeles waltlii: comparison with myosin from skeletal muscles.

Myosin extracted from ventricular muscle of the urodelan amphibian Pleurodeles waltlii was analyzed in comparison with myosin extracted from skeletal muscles by native, one-dimensional SDS gel electrophoresis and two-dimensional gel electrophoresis. Two myosin isoforms were detected in ventricular muscle using pyrophosphate gel electrophoresis. These isomyosins contained two types of light chain subunits, LC1v and LC2v. Two-dimensional gel electrophoresis showed that LC1v comigrated with the slow light chain LC1s, whereas LC2v was characterized by a specific mobility, distinct from LC2s and LC2f. Diaphragm muscle was characterized by the coexistence of larval and adult myosin isoforms.