Imino-oxy Acetic Acid Dealkylation as Evidence for an Inner-Sphere Alcohol Intermediate in the Reaction Catalyzed by Peptidylglycine α-Hydroxylating Monooxygenase
作者:Neil R. McIntyre、Edward W. Lowe、David J. Merkler
DOI:10.1021/ja902716d
日期:2009.7.29
stereospecific hydroxylation of a glycyl alpha-carbon in a reaction that requires O(2) and ascorbate. Subsequent dealkylation of the alpha-hydroxyglycine by another enzyme, peptidylamidoglycolate lyase (PAL. EC 4.3.2.5), yields a bioactive amide and glyoxylate. PHM is a noncoupled, type II dicopper monooxygenase which activates O(2) at only a single copper atom, Cu(M). In this study, the PHM mechanism was probed
肽基甘氨酸 α-羟基化单加氧酶 (PHM,EC 1.14.17.3) 在需要 O(2) 和抗坏血酸的反应中催化甘氨酰 α-碳的立体定向羟基化。随后通过另一种酶肽酰氨基乙醇酸裂解酶 (PAL. EC 4.3.2.5) 对 α-羟基甘氨酸进行脱烷基化,产生生物活性酰胺和乙醛酸。PHM 是一种非偶联的 II 型双铜单加氧酶,它仅在单个铜原子 Cu(M) 上激活 O(2)。在这项研究中,使用非天然底物苯甲醛亚氨基氧乙酸 (BIAA) 探索了 PHM 机制。PHM 在不涉及 PAL 的情况下催化 BIAA 的 O-氧化脱烷基为苯甲醛肟和乙醛酸盐。BIAA 的最小动力学机制显示为稳态有序使用初级氘动力学同位素效应。(D)(V/K)(APPARENT, BIAA) 从 14 下降。7 +/- 1.0 as [O(2)] --> 0 到 1.0 +/- 0.2 as [O(2)] --> 无穷大表明 PHM