title: Classification and characterization of cardiac isomyosins.
abstract: The structural properties of cardiac isomyosins from several species were compared using native gel electrophoresis, analysis of proteolytic digests, analysis of monoclonal antibody reactivity to specific proteolytic fragments on electroblots and S1 nuclease mapping with cDNA probes. The structure of specific regions of the myosin molecule was analyzed by reacting monoclonal antibodies with chymotryptic peptides of myosin separated by two-dimensional electrophoresis. The pattern of fragments reactive with antibody CCM-52 (epitope in LMM) was identical in all types of V3 isomyosin examined, and different in each type of V1 isomyosin. Peptides reactive with RCM-79 (epitope in HMM) were different from those reactive with CCM-52 and were also significantly different in each type of myosin examined. Thus, HC-alpha is structurally similar in the LMM portion of the molecule in all animals examined, while in the HMM region there are significant structural differences. HC-alpha differs from HC-beta, with structural differences in both LMM and HMM. We have also shown that atrial myosin HC and ventricular HC-alpha in the rabbit are indistinguishable both by RIA and peptide mapping analysis. The same conclusion was derived after analysis of the myosin HC mRNA expressed in rabbit atria and ventricles. Using cDNA probes specific for the alpha and beta myosin HC mRNA, we could not distinguish between the atrial myosin mRNA and ventricular HC alpha (V1 isomyosin) mRNA by S1 nuclease mapping experiments. Classification of different cardiac myosins is largely based on their mobility on native gel electrophoresis, immunological cross-reactivity, and ATPase activities.(ABSTRACT TRUNCATED AT 250 WORDS)
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal; D002417:Cattle; D002645:Chickens; D003429:Cross Reactions; D004285:Dogs; D004586:Electrophoresis; D006168:Guinea Pigs; D006801:Humans; D007527:Isoenzymes / Q000032:analysis / Q000302:isolation & purification*; D051379:Mice; D008854:Microscopy, Electron; D009206:Myocardium / Q000032:analysis*; D009218:Myosins / Q000032:analysis / Q000302:isolation & purification*; D011817:Rabbits; D011863:Radioimmunoassay; D051381:Rats; D013552:Swine
chemical_list: D000911:Antibodies, Monoclonal; D007527:Isoenzymes; D009218:Myosins