Pathways of calcium release from heavy sarcoplasmic reticulum vesicles isolated from rabbit skeletal muscle

FEBS Letters

Rubtsov, Alexander M.¹  Quinn, Peter J.²  Boldyrev, Alexander A.¹ 

[1] Department of Biochemistry, Moscow State University, Moscow 119899, USSR;Department of Biochemistry, King's College, London, Campden Hill, London W8 7AH, England

关键词: C2+ channel;    Sarcoplasmic reticulum;    Ca2+ -ATPase;    Membrane transport;   

DOI  :  10.1016/0014-5793(88)80487-3

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The active uptake and efflux of Ca²⁺ from suspensions of vesicles from heavy rabbit muscle sarcoplasmic reticulum have been examined using the antipyrylazo III dye method in the presence of various nueleotide triphosphate substrates to support active Ca²⁺ accumulation. On addition of ATP, Ca²⁺ is rapidly accumulated and maintained at high internal concentrations until the substrate for pump protein is exhausted. Ca²⁺ -induced Ca²⁺ release which is inhibited by ruthenium red can be demonstrated. The kinetics of Ca²⁺ release via these channels is different from the Ca²⁺ efflux observed after substrate exhaustion. This rate was found to be dependent on the type of nucleotide triphosphate, decreasing in the order ATP > GTP > CTP > ITP UTP. It is suggested that different conformations of the Ca²⁺ pump protein induced by the different substrates may result in the creation of pathways for the facilitated diffusion of Ca²⁺.

【 授权许可】

Unknown