囊泡表面氨基酸信号分子与维生素B_6衍生物受体反应平衡常数的估计

Estimation of the chemical equilibrium constants for amino acid signal molecules and a pyridoxal derivative receptor on bilayer vesicles

为了构建一个新的以维生素B_6衍生物(PL^+C_(16))为受体、氨基酸为信号分子的人工细胞信号转导超分子体系,测定在40℃、pH值分别为7.0、8.0及9.0的缓冲液体系下,4种信号分子(甘氨酸、β-丙氨酸、γ-氨基丁酸、天冬氨酸)在不同初始浓度下与受体PL^+C_(16)反应的吸光度,通过用MATLAB模型拟合工具包将其实验数据进行非线性拟合,估计反应的平衡常数K,定量考察了4种信号分子到达人工细胞膜载体表面与受体分子的结合能力。结果表明:不同pH值下,同一氨基化合物与受体PL^+C_(16)反应的平衡常数K有明显差异,而在同一pH值下,不同氨基酸与受体的K值也有很大差别,其中pH值为9.0时,天冬氨酸的K值最大,与受体PL^+C_(16)的结合能力最强。

To construct a novel artificial signal transduction supper molecular system whose receptor is a pyridoxal derivative （PL^＋C16） and signal molecule is amino acid, combination abilities of the receptor PL^＋C16 and different signal molecules have been investigated. 12 groups of experiments were first conveyed at 40℃, under various condition combinations of signal molecule （glycine,β-alanine, γ-aminobutyric acid and aspartic acid） and pH values of buffer （7.0, 8.0 and 9.0）. In each group of experiments, a series of absorbance values of reacting substances were measured corresponding different initiation concentrations of signal molecule. Then the results were modeled and fitted into nonlinear curves using the toolbox provided by MATLAB. Thus, the value of equilibrium constant K can be estimated and a quantitative assessment of the combination ability can be achieved. The experiment results show that the values of equilibrium constant K have significant difference using the same amino acid but different buffer pH values in reaction of receptor PL＋C^6 and signal molecule, and the constant K varies distinctively when keeping the pH values the same but using different kinds of amino acid. The results also show that the constant K becomes the largest when using aspartic acid as the signal molecule and the buffer pH is 9.0, and under this condition, the signal molecule exhibits the best combination ability with receptor PL^＋C16.