New Spectral Species of l-Lysine Monooxygenase, a Flavoprotein

Abstract

Abstract Several new spectral species of the prosthetic flavin were found during reactions of l-lysine monooxygenase. Immediately after the addition of lysine to the enzyme, the absorption of the enzyme-bound FAD increased slightly around 375 to 385 nm either in the presence of oxygen or in its absence. During anaerobic reduction of FAD with lysine, a short lived broad absorption band appeared in the long wave length region centered around 550 nm. In contrast, under aerobic conditions, another new spectral species appeared in the steady state of reaction, which, unlike the oxidized or reduced form of the enzyme, exhibited a long wave length absorption centering around 575 nm. This species was distinct from that observed in the anaerobic reaction and was also characterized by an absorption peak at about 455 nm, shifted from 460 nm. The presence of both oxygen and lysine was required for the appearance of this spectral species.