title: Cu(II)-mediated phenol oxygenation: chemical evidence implicates a unique role of the enzyme active site in promoting the chemically difficult tyrosine monooxygenation in TPQ cofactor biogenesis of copper amine oxidases.
abstract: Cu(II)-mediated autoxidations of 4-tert-butylphenol under various conditions was studied, the data confirmed imidazole is the best ligand to promote phenol oxygenation. The same reaction of 2,4-di-tert-butylphenol proceeded much more quickly to lead nearly exclusively to oxidative coupling rather than oxygenation under high pressure O2. These results suggested that Cu(II)-catalyzed phenol autoxidation by activating O2 and phenol in terms of a phenoxy radical (ArO)-Cu(II)-superoxide ternary complex, whereas selectivity between oxygenation and coupling depends mainly on the electronic structure of ArO. It is appeared that CuAOs could achieve stoichiometric tyrosine monooxygenation by modulating the redox potential of Cu(II) and stabilizing the ternary complex through protein conformational adjustment.
authors: College of Chemistry, Nanchang University, Nanchang 330031, China.
authors: Zhengjiang
authors: Z
authors: Fu
authors: College of Chemistry, Nanchang University, Nanchang 330031, China.
authors: Feng
authors: F
authors: Xu
authors: College of Chemistry, Nanchang University, Nanchang 330031, China. Electronic address: caihu@ncu.edu.cn.
authors: Hu
authors: H
authors: Cai
mesh_terms: D006631:Amine Oxidase (Copper-Containing) / Q000737:chemistry / Q000378:metabolism*; D020134:Catalytic Domain; D003067:Coenzymes / Q000378:metabolism; D003300:Copper / Q000378:metabolism*; D004295:Dihydroxyphenylalanine / Q000031:analogs & derivatives* / Q000378:metabolism; D010084:Oxidation-Reduction; D010100:Oxygen / Q000378:metabolism*; D010636:Phenols / Q000378:metabolism*; D014443:Tyrosine / Q000378:metabolism*
chemical_list: C086758:2,4,5-trihydroxyphenylalanine quinone; D003067:Coenzymes; D010636:Phenols; C042329:phenoxy radical; D014443:Tyrosine; D004295:Dihydroxyphenylalanine; D003300:Copper; D006631:Amine Oxidase (Copper-Containing); C056559:2,4-di-tert-butylphenol; C006862:butylphen; D010100:Oxygen
keywords: Biogenesis; Copper; Enzyme; Oxygenation