Biochemical characteristics of human cardiac myosin

Abstract

Myosin was purified from the left ventricles of eight patients. Samples of the ventricle were obtained immediately after the death of three patients whereas the rest were obtained from 2 1 2 to 20 h after the death. Human cardiac myosin, like the cardiac myosin from other mammalian species has only two light chains. The corresponding molecular weights were 26000 and 20000 for light chain 1 (LC 1) and light chain (LC 2) respectively. In its chemical properties, total sulfhydryl groups and responses to solvents the human cardiac myosin resembles canine cardiac myosin. These studies also show that a delay in the preparations of myosin up to 20 h does not alter its properties. ATPase activities (Ca 2+, Mg 2+ and K +-EDTA) did not show any correlation with the age of the subject. However the total-SH content was significantly lower in the elderly patients.