Holm J, Hansen S I, Lyngbye J
Clin Chim Acta. 1980 Jan 15;100(2):113-9. doi: 10.1016/0009-8981(80)90072-8.
The binding pattern of [3H]folate in the serum of male subjects was studied in equilibrium dialysis experiments (pH 7.4, 37 degrees C). It was possible to distinguish between a high (association constant, Kass = 10(10) (mol/l)-1; maximum binding of folate = 0.6 nmol/l) and a low affinity type of binding. The high-affinity binder was a trace protein (molecular size approximately 35 000) which was eluted with 30 mmol/l NaC, (pH 6.3) from serum subjected to DEAE-Sepharose CL-6B chromatography. The low-affinity binding activity mainly associated with albumin was eluted with 1 mmol/l NaCl. High-affinity binding was depressed at 7 degrees C (Kass = 10(9) (mol/l)-1). Furthermore, methotrexate acted as a weak inhibitor of high-affinity binding, the molar methotrexate/folate ratio being 100/1 at 50% inhibition.
在平衡透析实验（pH 7.4，37℃）中研究了男性受试者血清中[3H]叶酸的结合模式。可以区分出高亲和力（缔合常数，Kass = 10(10) （mol/l）-1；叶酸最大结合量 = 0.6 nmol/l）和低亲和力的结合类型。高亲和力结合物是一种微量蛋白质（分子大小约为35000），在用DEAE-琼脂糖CL-6B色谱法处理的血清中，用30 mmol/l NaCl（pH 6.3）洗脱。主要与白蛋白相关的低亲和力结合活性用1 mmol/l NaCl洗脱。高亲和力结合在7℃时受到抑制（Kass = 10(9) （mol/l）-1）。此外，甲氨蝶呤是高亲和力结合的弱抑制剂，在50%抑制时甲氨蝶呤/叶酸的摩尔比为100/1。
