Conversion of N,N-dimethylaniline to N,N-dimethylaniline-N-oxide by a cytosolic flavin-containing enzyme from Trypanosoma cruzi.

A cytosolic NADPH-dependent FAD-containing enzyme purified from Trypanosoma cruzi epimastigotes [Kuwahara, White, and Agosin: Biochem. Biophys. Res. Commun. 124, 121 (1984); Arch. Biochem. Biophys. 239, 18 (1985)] catalyzes the conversion of N,N-dimethylaniline to its corresponding N-oxide. The identity of the product has been established by high performance liquid chromatography and paper chromatography elution patterns and by electron impact spectrometry. The oxidation of N,N-dimethylaniline was determined by following the oxidation of NADPH spectrophotometrically, and a double reciprocal plot of reaction velocity vs. substrate concentration was prepared. At an optimum pH of 8.0, the plot resulted in Km and Vmax values of 56 microM and 114 nmol X min-1 X mg of protein-1, respectively. The oxidative activity of the enzyme suggests that it may be involved in detoxication processes which may contribute to the resistance of T. cruzi to known antiprotozoal drugs.