Myosin Isoforms in Normal and Dystrophic Human and Murine Muscles
Myosin is the contractile protein in muscle which forms the cross-bridge with actin to transduce the free energy of hydrolysis of ATP into mechanical work and heat, The rate of energy transduction is a function of the kinetics of myosin as a mechano-enzyme. Myosin exists as a large family of isoenzymic forms differing from each other in subunit composition, ATPase activity and consequently the rate of energy transduction. The functional significance of myosin polymorphism lies in the fact that each type of muscle fiber has its unique type of isomyosin which determines its intrinsic contractile dynamics. This diversity of isomyosin types is matched by the wide range of muscle fiber types. Muscle fibers associated with a specific isomyosin type may also have different isoforms of other myofibrillar proteins as well as varying proportions of glycoltyic and oxidative enzymes. These differences allow muscle fibers with different contractile properties to be classified histochemically into a number of types.
KeywordsSpinal Muscular Atrophy Extensor Digitorum Longus Extensor Digitorum Longus Muscle Dystrophic Muscle Myosin ISOFORMS
Unable to display preview. Download preview PDF.