Pyridine as novel substrate for regioselective oxygenation with aromatic peroxygenase fromAgrocybe aegerita

Agrocybe aegerita peroxidase (AaP) is a versatile extracellular biocatalyst that can oxygenate aromatic com- pounds. Here, we report on the selective oxidation of pyridine (PY) yielding pyridine N-oxide as sole product. Using H2 18 O2 as co-substrate, the origin of oxygen was confirmed to be the per- oxide. Therefore, AaP can be regarded as a true peroxygenase transferring one oxygen atom from peroxide to the substrate. To our best knowledge, there are only two types of enzymes oxi- dizing PY at the nitrogen: bacterial methane monooxygenase and a few P450 monooxygenases. AaP is the first extracellular enzyme and the first peroxidase that catalyzes this reaction, and it converted also substituted PYs into the corresponding N-oxides. � 2008 Federation of European Biochemical Societies. Pub- lished by Elsevier B.V. All rights reserved.