ABSTRACT
The multisubstrate flavin adenine dinucleotide containing monooxygenases (MFMO) are widely distributed in higher organisms and may be essential in more than one physiological function. Although the MFMO are relatively nonspecific for xenobiotics, they show a very high specificity for potential physiological substrates. The multisubstrate flavin-containing monooxygenases catalyze oxygenation of a wide range of xenobiotic compounds, however, extensive studies on substrate specificity are only available for the hog liver enzyme. The enzyme is most abundant in liver tissue, with somewhat lesser amounts in kidney and lung tissue. The hog liver MFMO is an allosteric enzyme and contains a distinguishable second site which binds compounds that modify the catalytic activity of the enzyme. The activity of the liver, kidney, and lung enzyme is readily identified and measured in whole homogenates and subcellular fractions by following the N-oxidation of dimethy-laniline using a colorimetrie method developed by D. M. Ziegler and F. H. Pettit.
