Enzymatic reactions involving novel mechanisms of carbanion stabilization

被引：44

作者：

Begley, TP ^{[1
]}

Ealick, SE ^{[1
]}

机构：

[1] Cornell Univ, Dept Chem & Biol Chem, Ithaca, NY 14853 USA

来源：

CURRENT OPINION IN CHEMICAL BIOLOGY | 2004年 / 8卷 / 05期

关键词：

D O I：

10.1016/j.cbpa.2004.08.004

中图分类号：

Q5 [生物化学]; Q7 [分子生物学];

学科分类号：

071010 ; 081704 ;

摘要：

The reactions catalyzed by orotidine monophosphate decarboxylase, oxalate decarboxylase, organomercurial lyase and phosphopantothenoylcysteine decarboxylase involve putative high-energy carbanion intermediates that cannot be stabilized by delocalization. Mechanistic and structural studies on each of these enzymes are described that suggest different strategies for carbanion stabilization. Both orotidine monophosphate decarboxylase and organomercurial lyase are likely to avoid carbanion formation by protonating the fragmenting bond, oxalate decarboxylase stabilizes an acyl carbanion using an adjacent radical and phosphopantothenoylcysteine decarboxylase stabilizes its carbanion by delocalization into a transient thioaldehyde.

引用

页码：508 / 515

页数：8

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