来自太平洋褶柔鱼外套膜和虾夷扇贝闭壳肌的重酶解肌球蛋白及亚片段-1的钙结合与钙敏感性

Calcium binding and calcium-sensitivity of heavy meromyosin and subfragment-1 from squid (Todarodes pacificus) mantle and scallop (Patinopecten yessoensis) adductor muscles.

Kamiya S, Konno K

Department of Food Science, Faculty of Fisheries, Hokkaido University, Japan.

Comp Biochem Physiol B. 1989;92(3):481-6. doi: 10.1016/0305-0491(89)90120-x.

Abstract

HMM and S-1 both bind one mol of calcium per mole of head, and a half of the calcium binding was diminished upon magnesium addition (10 mM) at the low affinity site. 2. The Mg-ATPase activity of HMM (without actin) was fully activated by the binding of one mol of calcium bound per mol of HMM. 3. The calcium binding profile to S-1 is the same as that to HMM, however, the Mg-ATPase activity of S-1 is independent of calcium binding. It is suggested that there are two kinds of myosin head (or S-1) in molluscan myosin, functionally different in calcium binding properties.

摘要

HMM和S-1每摩尔头部均结合1摩尔钙，在低亲和力位点添加镁（10 mM）后，一半的钙结合减少。2. HMM（无肌动蛋白）的Mg-ATP酶活性通过每摩尔HMM结合1摩尔钙而被完全激活。3. S-1的钙结合曲线与HMM相同，然而，S-1的Mg-ATP酶活性与钙结合无关。提示软体动物肌球蛋白中存在两种肌球蛋白头部（或S-1），在钙结合特性上功能不同。