Garrell J, Cuchillo C M
FEBS Lett. 1985 Oct 14;190(2):329-32. doi: 10.1016/0014-5793(85)81312-0.
The reaction of alpha-chymotrypsin with AcTyr-OEt and with AcTrp-OEt at pH 7.0 and 7.8 was studied over a wide range of substrate concentrations. The reaction with AcTyr-OEt at pH 7.8 was shown to be non-hyperbolic using a variety of criteria whereas those at pH 7.0 with the same substrate and at both pH values with AcTrp-OEt were hyperbolic. The non-hyperbolicity of the reaction with AcTyr-OEt at pH 7.8 followed a pattern of negative cooperativity with a Hill coefficient for the high substrate concentration range of 0.48. Although other explanations are possible, the pH dependence of the reaction with AcTyr-OEt could be related to the slow transition of the two known forms of the enzyme.
在广泛的底物浓度范围内，研究了α-胰凝乳蛋白酶在pH 7.0和7.8时与乙酰酪氨酸乙酯（AcTyr-OEt）以及与乙酰色氨酸乙酯（AcTrp-OEt）的反应。使用多种标准表明，在pH 7.8时与AcTyr-OEt的反应是非双曲线型的，而在pH 7.0时与相同底物的反应以及在两个pH值下与AcTrp-OEt的反应均为双曲线型。在pH 7.8时与AcTyr-OEt的反应的非双曲线性遵循负协同性模式，在高底物浓度范围内的希尔系数为0.48。尽管可能有其他解释，但与AcTyr-OEt的反应对pH的依赖性可能与该酶两种已知形式的缓慢转变有关。
