Soliman H A, Olesen H
Scand J Clin Lab Invest. 1976 May;36(3):299-304.
Binding of [3H]folate to pure human plasma albumin was studied by Sephadex G-200 gel filtration in a steady-state system. The experiments showed the presence of two binding sites per molecule of albumin and an equilibrium constant of 0.9x10(3) 1/mol. With normal human plasma, only albumin bound exogenous [3H]folate with nearly the same equilibrium constant. In human blood plasma at concentrations of less than 10(-5) mol/1, 50% of folate was free, and 50% was bound to albumin. Binding was maximal at about pH 6 and negligible above pH 8 and below pH 4.5. Neither human transferrin nor Cohn fraction II was able to bind [3H]folate.
在稳态系统中，通过葡聚糖凝胶G - 200凝胶过滤法研究了[3H]叶酸与人纯血浆白蛋白的结合情况。实验表明，每分子白蛋白存在两个结合位点，平衡常数为0.9×10³ 1/mol。对于正常人血浆，只有白蛋白结合外源性[3H]叶酸，且平衡常数几乎相同。在浓度低于10⁻⁵ mol/1的人血浆中，50%的叶酸是游离的，50%与白蛋白结合。结合在pH约为6时最大，在pH高于8和低于4.5时可忽略不计。人转铁蛋白和科恩II组分均不能结合[3H]叶酸。
