title: Correlation between myofibrillar ATPase activity and myosin heavy chain composition in rabbit muscle fibers.
abstract: Combined histochemical and biochemical analyses were performed on single fibers of rabbit soleus muscle. Histochemically, four fiber types (I, IC, IIC, IIA) were defined. Of these, types I and IIA were separate, histochemically homogeneous groups. A heterogeneous C fiber population exhibited a continuum of staining intensities between types I and IIA. Microelectrophoretic analyses of specific, histochemically defined fibers revealed that type I fibers contained exclusively HCI, whereas type IIA fibers contained only HCIIa. The C fibers were characterized by the coexistence of both heavy chains in varying ratios, type IC with a predominance of HCI and type IIC with a predominance of HCIIa. A direct correlation existed between the myosin heavy chain composition and the histochemical mATPase staining and was especially evident in the C fiber population with its variable HCI/HCIIa ratio. This correlation did not apply to the myosin light chain complement.
mesh_terms: D000251:Adenosine Triphosphatases / Q000032:analysis*; D000818:Animals; D004586:Electrophoresis / Q000379:methods; D006651:Histocytochemistry; D009132:Muscles / Q000378:metabolism*; D009210:Myofibrils / Q000201:enzymology*; D015879:Myosin Subfragments; D009218:Myosins / Q000032:analysis*; D010446:Peptide Fragments / Q000032:analysis; D011817:Rabbits; D013194:Staining and Labeling
chemical_list: D015879:Myosin Subfragments; D010446:Peptide Fragments; D000251:Adenosine Triphosphatases; D009218:Myosins