Abstract
Lipoamide dehydrogenase contains FAD and redox-acitve disulfide in its active center. The enzyme accepts two electron or four electrons under various conditions. In this paper we describe the electron transfer reaction mechanisms of NADH : lipoate reductase, NADH :osygen reductase, and NADH : menadione reductase. The enzyme catalyzed a mixed one-electron and two-electron reduction of oxygen and menadione, the two-electron transfer mechanism being dominant. The oxidase reaction is associated with fully-reduced flavin, and the menadione reductase reaction with half-reduced flavin. Furthermore, the superoxide radical generated by various reactions of the enzyme can reduce consecutively ferritin iron.
