Weidmann B, Abeles R H
Biochemistry. 1984 May 22;23(11):2373-6. doi: 10.1021/bi00306a008.
5-Butyl-3H-1,3-oxazine-2,6-dione (1) inactivates chymotrypsin. The extent of inactivation is dependent upon the concentration of 1. Upon dilution of the inactivated enzyme, catalytic activity is partially restored. Reactivation is a biphasic process. An initial relatively rapid phase (k = 1.8 X 10(-2) min), whose amplitude is dependent upon the extent of dilution, is observed. Maximally, 60-65% of the catalytic activity can be recovered. The rapid phase is followed by a slow phase (k approximately 1 X 10(-3) min-1). With 1 labeled with 14C at C-2, it was shown that two forms of inactive enzyme are formed, E.1 and E.1'. 14C label is retained in E.1 but is no longer present in E.1'. Presumably, C-2 is lost as CO2. The following reaction sequence is proposed for the inactivation of chymotrypsin: E + 1 in equilibrium E.1 CO2----E.1'----E + 1''. The probable structures of E.1, E . 1', and 1'' are shown in Scheme I in the text.
5-丁基-3H-1,3-恶嗪-2,6-二酮（1）可使胰凝乳蛋白酶失活。失活程度取决于1的浓度。将失活的酶稀释后，催化活性会部分恢复。再活化是一个双相过程。观察到一个初始相对快速的阶段（k = 1.8×10⁻²分钟⁻¹），其幅度取决于稀释程度。最大可恢复60 - 65%的催化活性。快速阶段之后是一个缓慢阶段（k约为1×10⁻³分钟⁻¹）。用在C-2位标记了¹⁴C的1进行实验，结果表明形成了两种无活性的酶形式，即E.1和E.1'。¹⁴C标记保留在E.1中，但在E.1'中不再存在。据推测，C-2位以二氧化碳的形式丢失。针对胰凝乳蛋白酶的失活提出了以下反应序列：E + 1 ⇌ E.1 → CO₂ → E.1' → E + 1''。文中方案I展示了E.1、E.1'和1''可能的结构。
