Distorted amides as models for activated peptide N-C:O units produced during enzyme-catalyzed acyl transfer reactions. 1. The mechanism of hydrolysis of 3,4-dihydro-2-oxo-1,4-ethanoquinoline and 2,3,4,5-tetrahydro-2-oxo-1,5-ethanobenzazepine
Attack of zwitterionic ammonium thiolates on a distorted anilide as a model for the acylation of papain by amides. A simple demonstration of a bell-shaped pH/rate profile
作者:J. W. Keillor、R. S. Brown
DOI:10.1021/ja00047a004
日期:1992.10
A distorted anilide (4) has been shown to be remarkably susceptible to attack by thiolates containing pendant N-H + groups. Thiolates alone are not reactive nor are amines or ammonium ions. Attack of the zwitterionic form produces a thiol ester+which is isolable in the case of N,N-dimethylcysteamine. If the pendant amine is primary, as in the case of cysteamine, the isolable product is the amide formed
扭曲的苯胺 (4) 已被证明非常容易受到含有悬垂 NH + 基团的硫醇盐的攻击。单独的硫醇盐没有反应性,胺或铵离子也没有反应性。两性离子形式的攻击产生硫羟酸酯+,其在N,N-二甲基半胱胺的情况下是可分离的。如果侧链胺是伯胺,如在半胱胺的情况下,可分离的产物是通过分子内 S 到 N 酰基转移形成的酰胺。2-(巯基甲基)-N-甲基咪唑 (1b) 在 4 上的反应动力学显示出钟形 pH 与 log k 2 曲线,这是由两性离子形式对酰胺的攻击引起的
Catalysis of Acyl Transfer from Amides to Thiolate Nucleophiles: The Reaction of a Distorted Anilide with Thioglycolic Acid and Ethyl 2-Mercaptoacetate
作者:B. A. Kellogg、A. A. Neverov、Ahmed M. Aman、R. S. Brown
DOI:10.1021/ja961312y
日期:1996.1.1
The kinetics and products of reaction of a distorted bicyclic anilide (1, 2,3,4,5-tetrahydro-2-oxo-1,5-ethanobenzazepine) with 2-mercaptoacetic acid (2, thioglycolicacid) and ethyl 2-mercaptoacetate (3) have been studied in H2O at 25 °C. In both cases the products are the corresponding thio esters. For 2, the pH rate profile shows an apparent plateau from pH 2 to 9, followed by a linear decrease in
The influence of a carboxylate group on the rate of O-acylation of 2-hydroxymethylimidazoles by a strained amide
作者:K. I. Skorey、V. Somayaji、R. S. Brown
DOI:10.1021/ja00223a057
日期:1988.7
Effet de la presence d'un groupe carboxylate dans les substituants des imidazolemethanols du titre
Effet de laexistence d'un groupe carboxylate dans les substituants des imidazolemethanols du titre
Molecular structure of 3,4,5-trihydro-2-oxo-1,5-ethanobenzazepine and its reaction with .beta.-amino alcohols as a model for the acylation step of the serine proteases
作者:V. Somayaji、K. I. Skorey、R. S. Brown、R. G. Ball
DOI:10.1021/jo00375a020
日期:1986.12
Reaction of a distorted amide with nucleophilic thiolate-containing zwitterions produced from thiolamines. A model for the acylation step in cysteine proteases and transglutaminases