Studies with Potential Reporter Group Reagents for Enzymes: 3,4-Dihydro-3-(2-Hydroxyethyl)-6-Nitro-2H-1,3-Benzothiazin-2-Thione and 6-Nitrochromone—Hydrolysis and Interaction with Chymotrypsin
作者:Trevor M. Kitson
DOI:10.1006/bioo.2000.1164
日期:2000.4
idea that chymotrypsin's “oxyanion hole” cannot properly accommodate a thioanion. II-HE undergoes an interesting intramolecular cleavage reaction under alkaline conditions. The mechanism of this process has been determined using evidence from NMR and mass spectrometry. 6-Nitrochromone (6-NC) likewise has the potential to modify an enzyme covalently and thereby act as a reporter group reagent. With chymotrypsin
摘要 3,4-Dihydro-3-(2-hydroxyethyl)-6-nitro-2H-1,3-benzothiazin-2-thione (II-HE) 是一种环状二硫代氨基甲酸酯,具有与酯酶反应提供它带有一个对硝基苯硫醇盐“报告基团”。然而,与非常相似的环状氨基甲酸酯不同,II-HE 对糜蛋白酶完全没有反应。讨论了用硫代替氧产生这种主要影响的可能原因。结果支持糜蛋白酶的“氧阴离子孔”不能正确容纳硫阴离子的观点。II-HE 在碱性条件下会发生有趣的分子内裂解反应。该过程的机制已使用来自 NMR 和质谱的证据确定。6-硝基色酮 (6-NC) 同样具有共价修饰酶的潜力,从而充当报告基团试剂。用糜蛋白酶,6-NC 反应与预期一致,只是所附标签仅在高 pH 条件下稳定;标记反应在低 pH 值下缓慢逆转。由于缺乏对酶活性的影响,很明显 6-NC 对糜蛋白酶的修饰不会发生在活性位点。