Katz A M, Shigekawa M, Repke D I, Hasselbach W
Recent Adv Stud Cardiac Struct Metab. 1976;11:205-12.
The slow rate of calcium transport by cardiac sarcoplasmic reticulum vesicles, compared to those prepared from skeletal muscle, is due mainly to a lesser density of transport sites and a lower Ca2+ affinity. Because the turnover rate of the cardiac sarcoplasmic reticulum calcium pump is similar to that of comparable skeletal muscle preparations, the cardiac sarcoplasmic reticulum seems able to effect the slower relaxation of the heart. Calcium permeability of skeletal sarcoplasmic reticulum vesicles is increased when the Ca2+ concentration outside the vesicles is increased, or when that inside the vesicle is decreased.
与从骨骼肌制备的囊泡相比，心肌肌浆网囊泡的钙转运速率较慢，这主要是由于转运位点密度较低以及Ca2+亲和力较低。由于心肌肌浆网钙泵的周转率与类似的骨骼肌制剂相似，心肌肌浆网似乎能够使心脏舒张更缓慢。当囊泡外部的Ca2+浓度增加或囊泡内部的Ca2+浓度降低时，骨骼肌肌浆网囊泡的钙通透性会增加。
