Enzymatic hydroxylation of aromatic compounds

• Published in: Cellular and molecular life sciences : CMLS Vol. 64; no. 3; pp. 271 - 293
• Main Authors: Ullrich, René, Hofrichter, Martin
• Format: Journal Article
• Language: English
• Published: Switzerland Basel : Birkhäuser-Verlag 01.02.2007; Springer Nature B.V; Birkhäuser-Verlag
• Subjects: Animals; Aromatic compounds; Binding Sites; Catalysis; Chemical reactions; Dioxygenase; Enzymes - metabolism; Free radicals; Humans; Hybrids; Hydrocarbons, Aromatic - chemistry; Hydrocarbons, Aromatic - metabolism; Hydrogen peroxide; Hydroxyl Radical - metabolism; Hydroxyl radicals; Hydroxylation; hydroxylradicals; laccase; monooxygenase; Oxygen; Oxygen transfer; P450; peroxidase; peroxygenase; Review; tyrosinase
• ISSN: 1420-682X; 1420-9071
• DOI: 10.1007/s00018-007-6362-1

Selective hydroxylation of aromatic compounds is among the most challenging chemical reactions in synthetic chemistry and has gained steadily increasing attention during recent years, particularly because of the use of hydroxylated aromatics as precursors for pharmaceuticals. Biocatalytic oxygen transfer by isolated enzymes or whole microbial cells is an elegant and efficient way to achieve selective hydroxylation. This review gives an overview of the different enzymes and mechanisms used to introduce oxygen atoms into aromatic molecules using either dioxygen (O₂) or hydrogen peroxide (H₂O₂) as oxygen donors or indirect pathways via free radical intermediates. In this context, the article deals with Rieske-type and α-keto acid-dependent dioxygenases, as well as different non-heme monooxygenases (di-iron, pterin, and flavin enzymes), tyrosinase, laccase, and hydroxyl radical generating systems. The main emphasis is on the heme-containing enzymes, cytochrome P450 monooxygenases and peroxidases, including novel extracellular heme-thiolate haloperoxidases (peroxygenases), which are functional hybrids of both types of heme-biocatalysts.