期刊
JOURNAL OF BIOLOGICAL CHEMISTRY
卷 276, 期 49, 页码 45902-45908出版社
AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC
DOI: 10.1074/jbc.M107434200
关键词
-
To understand mammalian skeletal myosin isoform diversity, pure myosin isoforms of the four major skeletal muscle myosin types (myosin heavy chains I, IIA, IIX, and IIB) were extracted from single rat muscle fibers. The extracted myosin (1-2 mug/15-mm length) was sufficient to define the actomyosin dissociation reaction in flash photolysis using caged-ATP (Weiss, S., Chizhov, I., and Geeves, M. A. (2000) J. Muscle Res. Cell Motil. 21, 423-432). The ADP inhibition of the dissociation reaction was also studied to give the ADP affinity for actomyosin (K-AD). The apparent second order rate constant of actomyosin dissociation gets faster (K(1)k(+2) = 0.17 -0.26 mum(-1).s(-1)), whereas the affinity for ADP is weakened (250-930 mum) in the isoform order I, IIA, IIX, IIB. Both sets of values correlate well with the measured maximum shortening velocity (V-0) of the parent fibers. If the value of KAD is controlled largely by the rate constant of ADP release (k(-AD)), then the estimated value of k(-AD) is sufficiently low to limit V.. In contrasts [ATP]K(1)k(+2) at a physiological concentration of 5 mm ATP would be 2.5-6 times faster than k(-AD).
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据