Studies on the pH-dependence of Myosin ATPase

　The fact that myosin ATPase has two optimal values of pH was discovered first by Engelhardt and Ljubimova in 1942（1）．They suggested that these pH optima might be explained by the ionization of the enzyme and the ionization of the substrate（1）．

　On the other hand, it was observed by Mehl（2）that myosin ATPase is inhibited reversibly by the treatment of hydrogen peroxide in alkali range．Then he considered that this phenomenon is resulted from the coexistence of two enzymes in his sample．And he attempted to separate these enzymes but was unable to achieve success．Recently, Mommaerts et al．