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钙是细胞内一种重要的调节细胞各种功能的信使。其哺乳动物细胞内浓度约为10~(-7)mo l/L。该浓度受Ca~(++)通道系统、离子交换机制、细胞内Ca~(++)储存和Ca~(++)泵的控制。Ca~(++)通道是质膜上的孔,经过它Ca~(++)沿着化学和/或电子梯度被动进入细胞内。在可兴奋细胞中这些通道受生理刺激或神经介质调节。Ca~(++)泵是一种对传出质膜的Ca~(++)具有高度亲和力的磷酸酶,其定位可通过一步法枸橼酸铅反应组化测定。该反应中ATP是底物,Ca~(++)是激活剂,铅
Calcium is an important messenger in cells that regulates various cellular functions. Its mammalian intracellular concentration of about 10 ~ (-7) mo l / L. This concentration is controlled by Ca ~ (++) channel system, ion exchange mechanism, intracellular Ca ~ (++) storage and Ca ~ (++) pump. The Ca ~ (++) channel is a pore in the plasma membrane through which Ca ~ (++) is passively introduced into the cell along chemical and / or electronic gradients. In excitable cells these channels are physiologically stimulated or regulated by the neurotransmitter. The Ca ~ (++) pump is a phosphatase with high affinity to Ca ~ (++) on the plasma membrane and its localization can be determined by one-step reaction of lead citrate. ATP is the substrate in this reaction, Ca ~ (++) is an activator of lead