Kosterin S A, Kurskiĭ M D, Burchinskaia N F
Biofizika. 1988 Sep-Oct;33(5):850-4.
It has been found that Ca-pump of the smooth muscle sarcolemma has much greater affinity to Ca2+ (Km = 0.5 M) than the system Na-Ca2+ of the exchanger (Km = 40-60 M). The maximal rate of Mg2+, ATP-dependent translocation of Ca2+ is 2-3 times higher than that of Na-dependent. The results of kinetic analysis show that Ca-pump of the smooth muscle sarcolemma is able to compensate the basal diffusion flow of this cation entering into unexcited cells of smooth muscle (5 x 10(-15) mol Ca2+ per 1 cm2 for 1 sec). It can also stationary support the value of Ca2+ concentration in relaxed myocytes on a physiologically significant level (10(-7)-10(-6) M).
已经发现，平滑肌肌膜的钙泵对Ca2+的亲和力（Km = 0.5 μM）比交换体的钠钙系统（Km = 40 - 60 μM）高得多。Mg2+、ATP依赖性的Ca2+转运最大速率比钠依赖性的高2 - 3倍。动力学分析结果表明，平滑肌肌膜的钙泵能够补偿该阳离子进入平滑肌未兴奋细胞的基础扩散流（每1平方厘米每秒5×10⁻¹⁵摩尔Ca2+）。它还能将舒张期心肌细胞中Ca2+浓度稳定维持在生理显著水平（10⁻⁷ - 10⁻⁶ M）。
