Studies on Monooxygenases

Crystalline l-lysine monooxygenase was shown to be homogeneous upon both ultracentrifugation and free boundary electrophoresis. On the basis of measurements of sedimentation constant, diffusion constant, and partial specific volume, the molecular weight of the enzyme was estimated to be 191,000. The reaction product was isolated and identified as δ-amino-n-valeramide based on melting point, elemental analyses, infrared absorption spectra, paper chromatography, and alkaline hydrolysis. Balance studies showed that 1 mole of l-lysine was converted to an equimolar amount each of δ-amino-n-valeramide and carbon dioxide with the consumption of 1 mole of oxygen. In addition to l-lysine the enzyme slowly oxidized l-ornithine, l-arginine, and l-thialysine. The enzyme was shown to contain 2 moles of flavin adenine dinucleotide, which were reduced by the anaerobic addition of l-lysine or the substrate analogues. δ-Amino-n-valeramide deaminase was also isolated and partially purified.