Calcium Regulation of the Conformational Change around a Specific Thiol Group, SH₂, of Skeletal Myosin

抄録

Conformational change induced by Mg²⁺-ATP in the local area containing a specific thiol group, SH₂, in skeletal myosin was regulated by physiological level of free Ca²⁺ concentration (pCa ranging from 8 to 4) . The curve relating conformational change to pCa in the presence of Mg²⁺-ATP has a characteristic sigmoid shape, showing an inflection point at pCa 5. This result suggests the presence of a Ca²⁺-dependent regulatory mechanism in skeletal myosin.