Biochemical properties of ordinary and dark muscle myosin from carp skeletal muscle.
Biochemical properties of ordinary and dark muscle myosin from carp skeletal muscle.
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DOI：
10.1093/jb/mvi121
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发表时间：
2005-09
影响因子：
2.7
通讯作者：
T. Okagaki;Masaki Takami;K. Hosokawa;M. Yano;S. Higashi-Fujime;A. Ooi
中科院分区：
文献类型：
--
作者：
T. Okagaki;Masaki Takami;K. Hosokawa;M. Yano;S. Higashi-Fujime;A. Ooi
从鲤鱼的普通肌（快肌）和暗肌（慢肌）中分离出两种类型的肌球蛋白，用ATP酶和离体运动试验对其进行了研究。普通肌球蛋白的ATP酶活性和滑动速度的Vmax比深色肌球蛋白高1.6和1.5倍，而哺乳动物的快肌球蛋白的活性和滑动速度的Vmax比慢肌球蛋白高3 ~ 10倍。虽然普通肌球蛋白的活性与哺乳动物快肌球蛋白几乎相同，但暗肌球蛋白的活性是哺乳动物慢肌球蛋白的两倍。暗肌球蛋白的这种高运动活性可以解释暗肌在鱼类巡航中的生理作用。通过比较肌动蛋白激活的ATP酶活性的Km值，发现普通肌球蛋白与F-actin的亲和力高于深色肌球蛋白，这一点在鲤鱼肌球蛋白的HMM或S-1与F-actin的结合实验中得到了证实。通过电子显微镜和离心分析的肌球蛋白组装的调查显示，普通肌球蛋白组装比暗肌球蛋白或哺乳动物快速肌球蛋白差得多。这种现象可能反映了鱼类骨骼肌特有的细胞功能。
Two types of myosin isolated from ordinary (fast) and dark (slow) muscles of carp were examined by ATPase and in vitro motility assays. Vmax of the ATPase activity and sliding velocity of ordinary myosin showed 1.6 and 1.5 times higher activities than those of dark myosin, whereas those of mammalian fast myosin were much higher, 3 to 10 times, than those of slow myosin. Although ordinary myosin had almost identical activities to those of mammalian fast myosin, activities of dark myosin was twice of those of mammalian slow myosin. This high motile activity of dark myosin can account for the physiological role of dark muscle in cruising of fish. By comparing Km of the actin-activated ATPase activity, ordinary myosin was appeared to have higher affinity to F-actin than dark myosin, and this was confirmed by the binding assay of HMM or S-1 of carp myosin to F-actin. Investigation of myosin assembly by electron microscopy and the centrifugation assay revealed that ordinary myosin assembled much poorly than dark myosin or mammalian fast myosin. This phenomenon may reflect characteristic cellular function of fish skeletal muscle.