Wikman-Coffelt J, Srivastava S
J Biochem. 1979 Sep;86(3):829-32. doi: 10.1093/oxfordjournals.jbchem.a132592.
From skeletal muscle myosin light chains readily dissociate from the myosin oligomer in the absence of divalent cations, and unlike rabbit skeletal muscle myosin light chains, the released light chains of frog skeletal muscle myosin have a high Ca2+ binding affinity. Whereas each Ca2+ binding light chain of frog skeletal muscle myosin, when in association with the heavy chains bound 1 mol of Ca2+, when in the dissociated state bound 0.5 mol of Ca2+; the latter were readily displaced with low Mg2+ concentrations. Whereas 10(-5) M Mg2+ displaced all of the Ca2+ binding sites on the released light chains at Ca2+ concentration ranges of 10(-7) to 10(-4) M, there was negligible displacement of the Ca2+ binding sites with native frog skeletal muscle myosin under these same conditions.
在没有二价阳离子的情况下，骨骼肌肌球蛋白轻链很容易从肌球蛋白寡聚体上解离下来。与兔骨骼肌肌球蛋白轻链不同，蛙骨骼肌肌球蛋白释放的轻链具有较高的Ca2+结合亲和力。蛙骨骼肌肌球蛋白的每条Ca2+结合轻链，与重链结合时结合1摩尔Ca2+，解离状态下结合0.5摩尔Ca2+；后者在低Mg2+浓度下很容易被取代。在Ca2+浓度范围为10(-7)至10(-4)M时，10(-5)M Mg2+取代了释放轻链上所有的Ca2+结合位点，而在相同条件下，天然蛙骨骼肌肌球蛋白的Ca2+结合位点几乎没有被取代。
