The actin‐activated ATPase of regulated and unregulated scallop heavy meromyosin

FEBS Letters

Jackson, Andrew P.¹  Wells, Christine¹  Warriner, Karen E.¹  Bagshaw, Clive R.¹ 

[1] Department of Biochemistry. University of Leicester, Leicester LEI 7RH, England

关键词: ATPase Heavy meromyosin Myosin-linked regulation Ca2+ activation;   

DOI  :  10.1016/0014-5793(86)80317-9

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Single-turnover kinetic analysis indicates that scallop heavy meromyosin (HMM) preparations contain a small fraction of unregulated molecules which dominate the steady-state ATPase activity in the absence of Ca²⁺. This fraction was removed by rapid centrifugation during an effective single turnover of the ATPase in the presence of actin. The maximum ATPase activity of a scallop myosin head was estimated as 10 s⁻¹ by cross-linking subfragment 1 to F-actin. HMM became Ca²⁺-insensitive during the cross-linking procedure. Attachment of spectroscopic probes to the reactive thiol group of scallop HMM resulted in the retention of ATPase activity but a loss in Ca²⁺ sensitivity.

【 授权许可】

Unknown