Diffusion-dependent kinetic properties of glyoxalase I and estimates of the steady-state concentrations of glyoxalase-pathway intermediates in glycolyzing erythrocytes.
Diffusion-dependent kinetic properties of glyoxalase I and estimates of the steady-state concentrations of glyoxalase-pathway intermediates in glycolyzing erythrocytes.
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乙二醛酶 I 的扩散依赖性动力学特性以及糖酵解红细胞中乙二醛酶途径中间体的稳态浓度估计。
DOI：
10.1111/j.1432-1033.1997.00852.x
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发表时间：
1997
期刊：
影响因子：
--
通讯作者：
Creighton,DJ
中科院分区：
文献类型：
--
作者：
Shih,MJ;Edinger,JW;Creighton,DJ
用粘度法测定了酵母乙二酸酶I反应的扩散相关动力学性质。以蔗糖为增粘剂，乙醛酶I催化谷胱甘肽-甲基乙二醛-硫代半缩醛-D-乳糖基谷胱甘肽的异构化反应，KCAT/Km(3.5x106M−1S−1，pH 7，25°C)随溶液粘度的增加而递减。这种粘度效应不太可能是由于蔗糖引起酶的本征动力学性质的改变，因为慢底物谷胱甘肽-叔丁基乙二醛硫代半缩醛(3.5x103M−1S−1，pH 7，25°C)的kcat/Km的大小与溶液粘度无关。利用斯托克斯-爱因斯坦扩散定律对数据进行的定量处理表明，在[底物]？Km的条件下，催化将是大约50%的扩散限制；酶和底物之间的相遇复合体在产物形成和解离之间的分配几乎相等，形成游离酶和底物。在一项相关的研究中，根据已公布的裂解红细胞中乙醛酶I和乙醛酶II的活性以及完整红细胞中D-乳酸的稳态形成速率，估计了人红细胞糖酵解过程中乙醛酶途径中间产物的稳态浓度在纳摩尔浓度范围内。这与乙醛酶途径的模型是一致的，在该模型中，酶催化的步骤在生理条件下受到显着的扩散限制。
The diffusion‐dependent kinetic properties of the yeast glyoxalase I reaction have been measured by means of viscosometric methods. For the glyoxalase‐I‐catalyzed isomerization of glutathione (GSH)‐methylglyoxal thiohemiacetal toS‐d‐lactoylglutathione, thekcat/Km(3.5 × 106M−1S−1, pH7, 25°C) undergoes a progressive decrease in magnitude with increasing solution viscosity, using sucrose as a visco‐genic agent. The viscosity effect is unlikely to be due to a sucrose‐induced change in the intrinsic kinetic properties of the enzyme, as the magnitude ofkcat/Kmfor the slow substrate GSH‐t‐butylglyoxal thiohemiacetal (3.5 × 103M−1s−1, pH 7, 25°C) is independent of solution viscosity. Quantitative treatment of the data by means of the Stokes‐Einstein diffusion law suggests that catalysis will be about 50% diffusion limited under conditions where [substrate] «Km; the encounter complex between enzyme and substrate partitions nearly equally between product formation and dissociation to form free enzyme and substrate. In a related study, the steady‐state concentrations of glyoxalase‐pathway intermediates in glycolyzing human erythrocytes are estimated to be in the nanomolar concentration range, on the basis of published values for the activities of glyoxalase I and glyoxalase II in lysed erythrocytes and the steady‐state rate of formation ofd‐lactate in intact erythrocytes. This is consistent with a model of the glyoxalase pathway in which the enzyme‐catalyzed steps are significantly diffusion limited under physiological conditions.
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pH 值和硫醇对酵母乙二醛酶 I 动力学的影响。随机途径机制的评估。
影响因子：
2.9
作者：
D. V. Vander Jagt;E. Daub;J. Krohn;L. Han
通讯作者：
L. Han
从人红细胞中纯化和表征乙二醛酶 II。
DOI：
--
发表时间：
1993
期刊：
European Journal of Biochemistry
影响因子：
--
作者：
R. E. Allen;T. W. Lo;Paul J Thornalley
通讯作者：
Paul J Thornalley
影响因子：
2.9
作者：
BROUWER, AC;KIRSCH, JF
通讯作者：
KIRSCH, JF
影响因子：
2.9
作者：
ALBERY, WJ;KNOWLES, JR
通讯作者：
KNOWLES, JR
[42] 甲醛脱氢酶
影响因子：
--
作者：
L. Uotila;M. Koivusalo
通讯作者：
M. Koivusalo