Yoshii T, Ishiyama I
Biochim Biophys Acta. 1983 Jan 12;742(1):235-42. doi: 10.1016/0167-4838(83)90381-3.
Binding constants for the interactions between Helix pomatia A hemagglutinin and the following saccharides were estimated at pH 7.0 and 25 degree C, using the circular dichroism method: N-acetyl-D-galactosamine, 5700 M-1; N-acetyl-D-glucosamine, 1000 M-1; melibiose, 86 M-1; raffinose, 350 M-1. The binding of N-acetyl-D-galactosamine to Helix pomatia A hemagglutinin was investigated in detail, using the circular dichroism and fluorescence methods, over the temperature range 5-50 degree C and pH range 7.0-2.5. The thermodynamic parameters, delta H degree (kcal . mol-1), delta G degree (kcal . mol-1), and delta S degree (e.u.), for this binding reaction at 25 degrees C were estimated as follows: -11.3, -5.24, -20.3 at pH 7.0; -9.1, -5.71, -11.2 at pH 4.5; -38.3, -3.19, -118 at pH 2.5. The negative values of delta H degrees and delta S degrees at pH 2.5 were especially large. This may be related to the restoration of the Helix pomatia A hemagglutinin molecule or its binding site from an unstable configuration caused by lowering the pH of the reaction medium to the original configuration of the presence of N-acetyl-D-galactosamine.
在pH 7.0和25℃条件下，使用圆二色性方法估算了蛾螺A血凝素与以下糖类之间相互作用的结合常数：N-乙酰-D-半乳糖胺，5700 M⁻¹；N-乙酰-D-葡萄糖胺，1000 M⁻¹；蜜二糖，86 M⁻¹；棉子糖，350 M⁻¹。使用圆二色性和荧光方法，在5 - 50℃温度范围和7.0 - 2.5 pH范围内，详细研究了N-乙酰-D-半乳糖胺与蛾螺A血凝素的结合。在25℃下，该结合反应的热力学参数，即ΔH°（千卡·摩尔⁻¹）、ΔG°（千卡·摩尔⁻¹）和ΔS°（熵单位）估算如下：pH 7.0时为-11.3、-5.24、-20.3；pH 4.5时为-9.1、-5.71、-11.2；pH 2.5时为-38.3、-3.19、-118。pH 2.5时ΔH°和ΔS°的负值特别大。这可能与蛾螺A血凝素分子或其结合位点从反应介质pH降低导致的不稳定构型恢复到N-乙酰-D-半乳糖胺存在时的原始构型有关。
