Oxidation of aldehydes catalyzed by pig liver flavin-containing monooxygenase.
Flavin-containing monooxygenase-1 (FMO1) purified to homogeneity from pig liver microsomes catalyzes NADPH- and oxygen-dependent oxidation of salicylaldehyde to pyrocatechol and formate. These products, formed in equimolar amounts, were the only ones detected that suggests that FMO1 catalyzes the oxidation of salicylaldehyde by Baeyer-Villiger chemistry. In addition to salicylaldehyde, 2-hydroxy-1-naphthaldehyde, 5-chlorosalicylaldehyde, 5-nitrosalicylaldehyde, ferrocene carboxaldehyde, 2-pyridine carboxaldehyde, and acetylacetone also stimulated NADPH-dependent oxygen uptake in the presence of FMO1. On the other hand, benzaldehyde, 2-methoxybenzaldehyde, 4-pyridine carboxaldehyde and 3- or 4-hydroxybenzaldehyde, and none of the alkylaldehydes tested had detectable substrate activity. Pig liver FMO1 apparently only catalyzes C-oxidation of reactive aldehydes with a hydrogen ion acceptor function adjacent to the carbonyl.
Chen
G P
GP
Department of Chemistry and Biochemistry, University of Texas, Austin 78712, USA.
Poulsen
L L
LL
Ziegler
D M
DM
D000447:Aldehydes / Q000378:metabolism*; D000818:Animals; D002384:Catalysis; D006863:Hydrogen-Ion Concentration; D007527:Isoenzymes / Q000378:metabolism*; D007700:Kinetics; D008099:Liver / Q000201:enzymology*; D008862:Microsomes, Liver / Q000201:enzymology; D010084:Oxidation-Reduction; D010105:Oxygenases / Q000378:metabolism / Q000494:pharmacology*; D013552:Swine
D000447:Aldehydes; D007527:Isoenzymes; C013243:salicylaldehyde; D010105:Oxygenases; C020066:dimethylaniline monooxygenase (N-oxide forming)