Actomyosin Alterations in Duchenne Muscular Dystrophy

Actomyosin isolated from Duchenne dystrophic muscle was studied with regard to adenosinetriphosphatase (ATPase) activity, ATPase pH stability, and superprecipitation activity. The decreased actomyosin Mg++ATPase activities in Duchenne muscular dystrophy correlated with the slower initial rates of superprecipitation. The Ca+ +and edetic acid—KCI stimulated ATPases were also lowered in the dystrophic actomyosins. The pH stability of dystrophic actomyosin ATPase was normal. These and all other changes described in the contractile proteins of Duchenne muscular dystrophy probably represent only quantitative alterations.