Spector A A, John K, Fletcher J E
J Lipid Res. 1969 Jan;10(1):56-67.
We have studied the binding of long-chain free fatty acids (FFA) to crystalline bovine serum albumin (BSA) that had been extracted with charcoal to remove endogenous fatty acids. The data were analyzed in terms of a model consisting of six high-energy binding sites and a large number of weak binding sites. The high-energy sites were resolved into two distinct classes, each containing three sites. At 37 degrees C and pH 7.4, k'(1) (the apparent association constant of a class of binding sites) was about 10(6) m(-1) for binding to the three primary sites, and k'(2) was about 10(5) m(-1) for binding to the three secondary sites. The number of weak (tertiary) sites was estimated to be 63 with a k'(3) of 10(3) m(-1). In general, palmitate and palmitoleate were bound more tightly than oleate, linoleate, stearate, or myristate, and much more tightly than laurate. The association of palmitate with human and rabbit albumin also was analyzed in terms of this model. Palmitate was bound less firmly by human or rabbit albumin than by BSA. Palmitate binding to BSA was dependent upon the pH and temperature of the incubation medium. Long-chain hydrocarbons that did not contain a free carboxyl group (methyl palmitate, cetyl alcohol, and hexadecane) were bound to a limited extent and weakly. The presence of positively charged protein sites and native protein tertiary structure were required for maximal binding of palmitate to BSA. Of nine other proteins tested, only -lactoglobulin exhibited a significant capacity to bind palmitate.
我们研究了长链游离脂肪酸（FFA）与经活性炭萃取以去除内源性脂肪酸的结晶牛血清白蛋白（BSA）的结合情况。数据按照一个由六个高能量结合位点和大量弱结合位点组成的模型进行分析。高能量位点被解析为两个不同的类别，每个类别包含三个位点。在37摄氏度和pH 7.4条件下，k'(1)（一类结合位点的表观缔合常数）对于与三个主要位点的结合约为10(6) m(-1)，而k'(2)对于与三个次要位点的结合约为10(5) m(-1)。弱（三级）位点的数量估计为63个，k'(3)为10(3) m(-1)。一般来说，棕榈酸酯和棕榈油酸酯的结合比油酸、亚油酸、硬脂酸或肉豆蔻酸更紧密，比月桂酸紧密得多。棕榈酸与人及兔白蛋白的结合也按照此模型进行了分析。棕榈酸与人或兔白蛋白的结合不如与BSA紧密。棕榈酸与BSA的结合取决于孵育介质的pH和温度。不含游离羧基的长链烃（棕榈酸甲酯、十六醇和十六烷）结合程度有限且较弱。棕榈酸与BSA的最大结合需要带正电荷的蛋白质位点和天然蛋白质三级结构的存在。在所测试的其他九种蛋白质中，只有β-乳球蛋白表现出显著的结合棕榈酸的能力。
