The enethiolate anion reaction products of EpiD - p kappa(alpha) value of the enethiol side chain is lower than that of the thiol side chain of peptides

被引:27
作者
Kupke, T
Gotz, F
机构
[1] Mikrobielle Genetik, Universität Tübingen, 72076 Tübingen
关键词
D O I
10.1074/jbc.272.8.4759
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
One of the steps involved in the biosynthesis of the lantibiotic epidermin is the oxidative decarboxylation reaction of peptides catalyzed by the flavoenzyme EpiD. EpiD catalyzes the formation of a (Z)-enethiol derivative from the C-terminal cysteine residue of the precursor peptide of epidermin and related peptides. The UV-visible spectra of the reaction products of EpiD are pH-dependent, indicating that the enethiol side chain is converted to an enethiolate anion. The pK(alpha), value of the enethiol group was determined to be 6.0 and is substantially lower than the pK(alpha) value of the thiol side chain of cysteine residues. The increased acid strength of the enethiol side chain compared with that of the thiol group is attributed to the resonance stabilization of the negative charge of the anion.
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页码:4759 / 4762
页数:4
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