Constantinides P P, Steim J M
Department of Chemistry, Brown University, Providence, Rhode Island 02912.
Arch Biochem Biophys. 1988 Mar;261(2):430-6. doi: 10.1016/0003-9861(88)90359-1.
The critical micelle concentrations (CMCs) of palmitoyl-CoA/stearoyl-CoA and palmitoyl-CoA/oleoyl-CoA mixtures in 0.050 M KPi, pH 7.4, a buffer used in enzymatic studies, were determined by fluorescence. Mixed micelle solution theory, analogous to the thermodynamic treatment of vapor pressure, was applied to calculate monomer and micelle compositions. The behavior of the palmitoyl-CoA/stearoyl-CoA mixture is ideal, while the palmitoyl-CoA/oleoyl-CoA mixture, although not exhibiting ideal behavior, can be fitted reasonably well by nonideal theory. In both mixtures, selective micellization takes place and, unlike the case of pure fatty acyl-CoAs, above the CMC of the mixtures the concentration of molecules free in solution is strongly dependent upon total concentration. The information derived from the present physical studies becomes important in enzymatic studies with membrane-bound acyltransferases, where selectivity toward various fatty acyl donors, presented as binary mixtures, is frequently observed.
在用于酶学研究的0.050 M磷酸钾（pH 7.4）缓冲液中，通过荧光法测定了棕榈酰辅酶A/硬脂酰辅酶A和棕榈酰辅酶A/油酰辅酶A混合物的临界胶束浓度（CMC）。应用类似于蒸气压热力学处理的混合胶束溶液理论来计算单体和胶束组成。棕榈酰辅酶A/硬脂酰辅酶A混合物的行为是理想的，而棕榈酰辅酶A/油酰辅酶A混合物虽然不表现出理想行为，但可以用非理想理论较好地拟合。在这两种混合物中，都发生了选择性胶束化，并且与纯脂肪酰辅酶A的情况不同，在混合物的CMC以上，溶液中游离分子的浓度强烈依赖于总浓度。从目前的物理研究中获得的信息在使用膜结合酰基转移酶的酶学研究中变得很重要，在这类研究中经常观察到对以二元混合物形式存在的各种脂肪酰供体的选择性。
