钙调蛋白是否调节人类红细胞钙离子泵对ATP的亲和力？
Does calmodulin regulate the affinity of the human red cell Ca2+ pump for ATP?
作者信息
Caride A J, Rossi J P, Garrahan P J, Rega A F
机构信息
Instituto de Química y Fisicoquímica Biológicas (UBA-CONICET), Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Argentina.
出版信息
Biochim Biophys Acta. 1990 Aug 10;1027(1):21-4. doi: 10.1016/0005-2736(90)90042-m.
(1) We have reexamined the effects of calmodulin and of the calmodulin antagonist, compound 48/80 on the interaction of ATP at its low-affinity site in the Ca2(+)-ATPase from human red cells. (2) At variance with our earlier proposal (Biochim. Biophys. Acta (1985) 816, 379-386) calmodulin increased the maximum effect of ATP without changing the apparent affinity for ATP at the low-affinity site. Accordingly, ATP increased the maximum activation by calmodulin without altering the apparent affinity of the Ca2(+)-ATPase for calmodulin. (3) Confirming our previous observation (Biochim. Biophys. Acta (1985) 816, 379-386) compound 48/80 lowered the apparent affinity of the Ca2(+)-ATPase for ATP at the low-affinity site. This has to be attributed to a direct effect of this compound on the enzyme rather than to its effect as calmodulin antagonist.
(1) 我们重新研究了钙调蛋白以及钙调蛋白拮抗剂化合物48/80对ATP在人红细胞Ca2(+)-ATP酶低亲和力位点相互作用的影响。(2) 与我们之前的提议（《生物化学与生物物理学报》(1985) 816, 379 - 386）不同，钙调蛋白增加了ATP的最大效应，而未改变其在低亲和力位点对ATP的表观亲和力。相应地，ATP增加了钙调蛋白的最大激活作用，而未改变Ca2(+)-ATP酶对钙调蛋白的表观亲和力。(3) 证实了我们之前的观察（《生物化学与生物物理学报》(1985) 816, 379 - 386），化合物48/80降低了Ca2(+)-ATP酶在低亲和力位点对ATP的表观亲和力。这必须归因于该化合物对酶的直接作用，而非其作为钙调蛋白拮抗剂的作用。
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