Hydroxylation of naphthalene by aromatic peroxygenase from Agrocybe aegerita proceeds via oxygen transfer from H2O2 and intermediary epoxidation.
Agrocybe aegerita peroxidase/peroxygenase (AaP) is an extracellular fungal biocatalyst that selectively hydroxylates the aromatic ring of naphthalene. Under alkaline conditions, the reaction proceeds via the formation of an intermediary product with a molecular mass of 144 and a characteristic UV absorption spectrum (A(max) 210, 267, and 303 nm). The compound was semistable at pH 9 but spontaneously hydrolyzed under acidic conditions (pH<7) into 1-naphthol as major product and traces of 2-naphthol. Based on these findings and literature data, we propose naphthalene 1,2-oxide as the primary product of AaP-catalyzed oxygenation of naphthalene. Using (18)O-labeled hydrogen peroxide, the origin of the oxygen atom transferred to naphthalene was proved to be the peroxide that acts both as oxidant (primary electron acceptor) and oxygen source.
Kluge
Martin
M
Unit of Environmental Biotechnology, International Graduate School of Zittau, Zittau, Germany. kluge@ihi-zittau.de
Ullrich
René
R
Dolge
Christoph
C
Scheibner
Katrin
K
Hofrichter
Martin
M
D055362:Agrocybe / Q000201:enzymology*; D006861:Hydrogen Peroxide / Q000378:metabolism*; D006900:Hydroxylation; D006899:Mixed Function Oxygenases / Q000378:metabolism*; D009281:Naphthalenes / Q000378:metabolism*; D009284:Naphthols / Q000378:metabolism; D010103:Oxygen Isotopes / Q000378:metabolism; D013194:Staining and Labeling
D009281:Naphthalenes; D009284:Naphthols; D010103:Oxygen Isotopes; C031721:naphthalene; C042033:naphthalene 1,2-oxide; C029350:1-naphthol; D006861:Hydrogen Peroxide; D006899:Mixed Function Oxygenases; C022333:peroxygenase; C028405:2-naphthol