Biochemical properties of ordinary and dark muscle myosin from carp skeletal muscle.
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.
Okagaki
Tsuyoshi
T
Department of Bioresources, Mie University, Kamihama 1515, Tsu, Mie 514-8507, Japan.
Takami
Masaki
M
Hosokawa
Kiyo
K
Yano
Miyuki
M
Higashi-Fujime
Sugie
S
Ooi
Atsushi
A
D000199:Actins / Q000378:metabolism; D000251:Adenosine Triphosphatases / Q000378:metabolism; D000818:Animals; D002347:Carps; D004789:Enzyme Activation; D018482:Muscle, Skeletal / Q000378:metabolism*; D009218:Myosins / Q000737:chemistry / Q000378:metabolism* / Q000648:ultrastructure; D011189:Potassium Chloride / Q000378:metabolism; D011485:Protein Binding; D011487:Protein Conformation
D000199:Actins; D011189:Potassium Chloride; D000251:Adenosine Triphosphatases; D009218:Myosins