INHIBITION OF HUMAN GLUTATHIONE-REDUCTASE BY THE NITROSOUREA DRUGS 1,3-BIS(2-CHLOROETHYL)-1-NITROSOUREA AND 1-(2-CHLOROETHYL)-3-(2-HYDROXYETHYL)-1-NITROSOUREA - A CRYSTALLOGRAPHIC ANALYSIS
INHIBITION OF HUMAN GLUTATHIONE-REDUCTASE BY THE NITROSOUREA DRUGS 1,3-BIS(2-CHLOROETHYL)-1-NITROSOUREA AND 1-(2-CHLOROETHYL)-3-(2-HYDROXYETHYL)-1-NITROSOUREA - A CRYSTALLOGRAPHIC ANALYSIS
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DOI：
10.1111/j.1432-1033.1988.tb13775.x
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发表时间：
1988-01-15
期刊：
影响因子：
--
通讯作者：
SCHULZ, GE
中科院分区：
文献类型：
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作者：
KARPLUS, PA;KRAUTHSIEGEL, RL;SCHULZ, GE
在准生理条件下，1，3-二（2-氯乙基）-1-亚硝基脲（BCNU）和1-（2-氯乙基）-3-（2-羟乙基）-1-亚硝基脲（HeCNU）对人红细胞谷胱甘肽还原酶有抑制作用。为了参考目的，使用碘乙酰胺使酶的烷基化失活。在每种情况下，修饰的谷胱甘肽还原酶结晶，并确定其结构。这些分析表明，在所有实验中，酶都在远端硫（即Cs-58的硫醇）处反应，而在可见结构中几乎没有其他地方。在0.3 nm分辨率下的HeCNU衍生物的电子密度与2-羟乙基一致。该烷基部分最近已通过化学分析鉴定[Schirmer，R.H.，Schollhammer，T.，Eisenbrand，G.和Krauth-Siegel，R.L. 03 The Dog of the Woman（1987）3，3-12]。BCNU衍生酶的0.2 nm分辨率电子密度图不能用2-羟乙基基团解释。相反，修饰表现为含有至少五个非氢原子的氨基甲酰基部分。在这种衍生物中，末端半胱氨酸被迫形成不寻常的构象。
Glutathione reductase from human erythrocytes was inhibited by incubation with the drugs 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) and 1-(2-chloroethyl)-3-(2-hydroxyethyl)-1-nitrosourea (HeCNU) under quasi-physiological conditions. For reference purposed, iodoacetamide was used for inactivating alkylation of the enzyme. In each case the modified glutathione reductase was crystallized and its structure determined. These analyses showed that in all experiments the enzyme had reacted at the distal sulfur, that is at the thiol of Cs-58, and virtually nowhere else in the visible structure. The electron density of the HeCNU derivative at 0.3 nm resolution is consistent with a 2-hydroxyethyl group. This alkyl moiety has recently been identified by chemical analysis [Schirmer, R.H., Schollhammer, T., Eisenbrand, G. and Krauth-Siegel, R.L. (1987) Free Radical Res. Commun. 3, 3-12]. The 0.2 nm resolution electron-density map of the BCNU-derivatized enzyme cannot be explained by a 2-hydroxyethyl group. Instead the modification appears as a carbamoyl moiety containing at least five non-hydrogen atoms. In this derivative the distal cysteine is forced into an unusual conformation.