可溶性钙结合蛋白对钙促进扩散的测量。

Measurement of facilitated calcium diffusion by a soluble calcium-binding protein.

作者信息

Feher J J

出版信息

Biochim Biophys Acta. 1984 Jun 13;773(1):91-8. doi: 10.1016/0005-2736(84)90553-4.

Abstract

The flux of calcium through an aqueous compartment was determined in a flow-dialysis cell in which two dialysis membranes separated the middle aqueous compartment from two outer compartments. The contribution of convection to the total calcium flux was large but could be removed by addition of 1% agar. The flux of calcium through the gelled aqueous compartment agreed with theoretical expectations. The self-diffusion coefficient for calcium from these results was calculated to be 0.81 X 10(-5) cm2 X s-1. Carp parvalbumin significantly enhanced the calcium flux at 2.3 X 10(-6)M free calcium. The calcium flux increased linearly with parvalbumin concentration. These observations are consistent with the hypothesis that the overall unidirectional calcium flux J is the sum of free calcium diffusion and protein-calcium diffusion: J = D[Ca] + D'[CaPr]. The value of D', the self-diffusion coefficient for parvalbumin, was calculated from the flux data to be 13.7 X 10(-7) cm2 X s-1.

摘要

在一个流动透析池中测定了钙通过水相室的通量，该透析池中有两个透析膜将中间的水相室与两个外部室隔开。对流对总钙通量的贡献很大，但加入1%的琼脂可以消除这种贡献。钙通过凝胶化水相室的通量与理论预期相符。根据这些结果计算出钙的自扩散系数为0.81×10⁻⁵ cm²·s⁻¹。鲤鱼小清蛋白在游离钙浓度为2.3×10⁻⁶M时显著增强了钙通量。钙通量随小清蛋白浓度呈线性增加。这些观察结果与以下假设一致，即总的单向钙通量J是游离钙扩散和蛋白质 - 钙扩散的总和：J = D[Ca] + D'[CaPr]。根据通量数据计算出小清蛋白的自扩散系数D'为13.7×10⁻⁷ cm²·s⁻¹。