Localization and histochemical characterization of myosin isoforms in earthworm body wall muscle

Myosin isolated from the body wall of the earthwormLumbricus terrestris contains three different myosin light chains with molecular weights of 28 (LC28), 25 (LC25), and 18 kDa (LC18). Two of them (LC28 and LC25), extractable with DTNB, were purified by Affi-Gel Blue and ion exchange chromatography and used to produce antibodies. Antibody staining revealed the presence of LC25 in nearly the whole body wall muscle except a small peripheral part of the longitudinal and circular muscle layer which contains only LC28. Several enzymatic activities are directly correlated with this differential distribution of light chains. The peripheral parts of both muscle layers exhibit low myosin and actomyosin ATPase and high succinic dehydrogenase activities.