Cuenda A, Nogues M, Gutiérrez-Merino C, de Meis L
Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias, Universidad de Extremadura, Badajoz, Spain.
Biochem Biophys Res Commun. 1993 Nov 15;196(3):1127-32. doi: 10.1006/bbrc.1993.2368.
In the presence of glycogen, ADP, phosphoglucomutase and hexokinase, the glycogen phosphorylase b activity associated to sarcoplasmic reticulum (SR) membranes stimulates Ca2+ uptake by SR membrane fragments in the absence of added ATP. Phosphoglucomutase and hexokinase lead to the formation of glucose 6-phosphate which in turn is used as an ATP regenerating system by the Ca2+ pump. It is proposed that a raise of cytosolic AMP and ADP concentrations after muscle contraction can activate an alternative metabolic route which would be used to ensure the maintenance of a low cytosolic Ca2+ concentration and avoid unnecessary metabolic energy depletion in muscle cells.
在糖原、二磷酸腺苷（ADP）、磷酸葡萄糖变位酶和己糖激酶存在的情况下，与肌浆网（SR）膜相关的糖原磷酸化酶b活性在未添加三磷酸腺苷（ATP）时会刺激SR膜片段对钙离子（Ca2+）的摄取。磷酸葡萄糖变位酶和己糖激酶会导致6-磷酸葡萄糖的形成，而6-磷酸葡萄糖又被Ca2+泵用作ATP再生系统。有人提出，肌肉收缩后胞质中腺苷一磷酸（AMP）和ADP浓度的升高可激活一条替代代谢途径，该途径可用于确保维持较低的胞质Ca2+浓度，并避免肌肉细胞中不必要的代谢能量消耗。
