Na(+)-Ca2+ exchange in locust striated muscles.
High Na+ + Ca2+ exchange rates comparable with those reported for crayfish striated muscle, rat heart and rat brain, were observed in locust striated muscle homogenates and membrane preparations. The Na(+)-Ca2+ exchange followed the 1st order kinetics with a Km value of 18 mumol.l-1 for Ca, the pH optimum was at 8, the temperature optimum at 30 degrees C, and the exchange was inhibited in the presence of sodium in the incubation medium, with a KiNa of approx. 25 mmol.l-1. The present results suggest a high Na(+)-Ca2+ exchange in locust striated muscles which operate on the calcium electrogenesis principle.
Juhászová
M
M
Institute of Molecular Physiology and Genetics, Slovak Academy of Sciences, Bratislava, Czechoslovakia.
Ruscák
M
M
Zachar
J
J
Novotová
M
M
D000818:Animals; D003400:Astacoidea / Q000378:metabolism; D001693:Biological Transport, Active; D002118:Calcium / Q000378:metabolism*; D002352:Carrier Proteins / Q000378:metabolism; D006110:Grasshoppers / Q000378:metabolism*; D007474:Ion Exchange; D007700:Kinetics; D009132:Muscles / Q000378:metabolism*; D051381:Rats; D012964:Sodium / Q000378:metabolism*; D019831:Sodium-Calcium Exchanger; D013347:Subcellular Fractions / Q000378:metabolism; D014018:Tissue Distribution
D002352:Carrier Proteins; D019831:Sodium-Calcium Exchanger; D012964:Sodium; D002118:Calcium