Smooth muscle energetics and theories of cross-bridge regulation

• DOI: 10.1152/ajpcell.1990.258.2.c369
• Publication Date: 2017-12-24T15:42:45Z
• Authors: R. J. Paul
• Keywords: CrossBridge; Dephosphorylation; Energetics; Adenosine triphosphate

The energetics of smooth muscle is characterized by low tension cost (rate ATP utilization per isometric force/cross-section area), ranging from 100- to 500-fold less than skeletal muscle. efficiency (ATP usage work) muscle, although well documented, also somewhat (4-fold) Another well-known characteristic the linear relation between steady-state (JATP) and force. Recently, Murphy colleagues [C.-M. Hai R. A. Murphy. Am. J. Physiol. 254 (Cell 23) C99-C106, 1988] have put forth a kinetic model cross-bridge regulation that predicts time course stress myosin light chain phosphorylation (MLC-Pi). consequences this model, in brief, are partly attributed slow detachment rate cross bridge when dephosphorylated attached actin ("latch state"), whereas lower ascribed high phosphorylation-dephosphorylation inherent fit data scheme. This latter corollary controversial current interpretations data. Using SCoP software (National Biomedical Simulation Resource, Duke University), we tested terms fitting existing with respect 1) myosin-dephosphorylation adenosine triphosphatase (ATPase) necessary available on MLC-Pi?; 2) can predict observed hydrolysis force?(ABSTRACT TRUNCATED AT 250 WORDS)