A mechanistic study of sialic acid mutarotation: Implications for mutarotase enzymes
作者:Jefferson Chan、Gurtej Sandhu、Andrew J. Bennet
DOI:10.1039/c1ob05079f
日期:——
by four kinetically distinct pathways: (i) the acid-catalyzed reaction of neutral Neu5Ac; (ii) the spontaneous reaction of the carboxylic acid (the kinetically equivalent acid-catalyzed reaction on the anion being ruled out by the solvent deuteriumkinetic isotope effect of 3.74 ± 0.68); (iii) a spontaneous, water-catalyzed, reaction of the anion; and (iv) a specific-base catalyzed reaction of the anion
的旋转 N-乙酰神经氨酸(Neu5Ac)通过四个动力学上不同的途径进行:(i)中性Neu5Ac的酸催化反应;(ii)羧酸的自发反应(通过3.74±0.68的溶剂氘动力学同位素效应排除了对阴离子的动力学等效酸催化的反应);(iii)阴离子的自发水催化反应;(iv)阴离子的特定碱催化的反应。溶剂动力学同位素效应的大小k H2O / k D2O = 4.48±0.74与开环过渡态一致,其中水分子与增强环氧原子的溶剂化作用一起使异头羟基脱质子。讨论了Neu5Ac诱变酶的机理。