Linear free energy relationships of the inhibition of pancreatic cholesterol esterase by 4-Nitrophenyl-N-alkylcarbamate
作者:Gialih Lin、Cheng-Yue Lai
DOI:10.1016/0040-4039(95)02126-4
日期:1996.1
4-Nitrophenyl-N-alkylcarbamates (1) as active site-directed irreversible inhibitors of pancreaticcholesterolesterase are investigated for values of the dissociation constant (Ki), the carbamylation constant (k2), and the bimolecular rate constant (ki). Linear free energy relationships between −logKi, logk2, or logki and polar substituent constant (σ∗) are observed. Taft's Es steric constants are
The enhancement of enantioselectivities for lipase-catalyzed reactions by using carbamates
作者:Gialih Lin、Wen-Yuan Lin、Chuen-Tzwu Shieh
DOI:10.1016/s0040-4039(98)02021-8
日期:1998.11
The enantioselectivity of porcine pancreatic lipase-catalyzed resolution of 1-indanol was enhanced up to 3 fold in the presence of carbamates. The optimum incubation time for 4-nitrophenyl-N-hexyl carbamate and the enzyme was 18 h before this biocatalytic resolution. The optimum concentration of the inhibitor 4-nitrophenyl-N-hexyl carbamate in this resolution was 1 % mole equivalent of the substrate 1-indanol. (C) 1998 Elsevier Science Ltd. All rights reserved.
Structure-Reactivity Relationships as Probes to Acetylcholinesterase Inhibition Mechanisms by Aryl Carbamates. II. Hammett-Taft Cross-Interaction Correlations
作者:Gialih Lin
DOI:10.1002/jccs.200400065
日期:2004.4
values for acetylcholinesteraseinhibitions by carbamates 1 correlate with the Hammett equation (log(k/k 0 ) = pa); moreover, those by carbamates 2 correlate with the Taft equation (log(k/k 0 ) = ρ* σ*). With modified Hammett-Taftcross-interaction variations, multiple linear regressions of the -logK i ' and logic values of carbamates 1 and 2 give good correlations, and the cross-interaction constants (ρ
取代的苯基-N-丁基氨基甲酸酯(1)和对硝基苯基-N-取代的氨基甲酸酯(2)被表征为乙酰胆碱酯酶的“假-假-底物”抑制剂。由于抑制剂在 pH 7.0 缓冲溶液中质子化,因此质子化抑制剂的虚拟抑制常数 (K i 's) 可通过以下等式计算:-logK i '= -logK i - pK a + 14。 -logK i '氨基甲酸酯 1 对乙酰胆碱酯酶抑制的 logk c 值与 Hammett 方程相关 (log(k/k 0 ) = pa);此外,氨基甲酸酯 2 与 Taft 方程 (log(k/k 0 ) = ρ* σ*) 相关。使用改进的 Hammett-Taft 交叉相互作用变化,-logK i ' 的多元线性回归和氨基甲酸酯 1 和 2 的逻辑值给出了良好的相关性,并且交叉相互作用常数 (ρ XR ) 为 0.5 和 0.0,分别。0.5 的 ρ XR 值表明导致酶-氨基甲酸酯四面体中间体的过渡态的氨基甲酸酯
Structure-Reactivity Relationships as Probes for the Inhibition Mechanism of Cholesterol Esterase by Aryl Carbamates. I. Steady-State Kinetics
作者:Gialih Lin、Cheng-Yue Lai、Wei-Cheng Liao、Bing-Hong Kuo、Chun-Ping Lu
DOI:10.1002/jccs.200000066
日期:2000.6
cies and fol lows the for ma tion of the rel a tively neu tral carbamyl en zymes. For the in hi bi tion of cho les t erol esterase by car ba mates 2 ex cept 4-nitrophenyl-N-phenyl carbamate and 4-nitrophenyl-N-t-butyl carbamate, lin ear re la tion ships of -logKi and logkc with * are ob served and the * val ues are -0.50 and 1.03, re spec tively. Since the above re ac tion also forms the neg a tive-charge