The presence of donors and carriers in the electron transport chain for trimethylamine N-oxide (TMO) reduction was investigated in Escherichi coli.
Formate, NADH, and NADPH were effective electron donore in the crude extract as well as membrane fraction from TMO-induced cells. The electron transfer from formate and NADH to TMO was inhibited by 2-hepty-4hydroxy-quinoline-N-oxide, suggesting the participation of b-type cytochromes. The inhibitor, however, failed to inhibit activity of TMO reductase linked to reduced methylviologen.
The functions of the cytochrome and reducase as electron carriers and the physiological importance of the above donors were discussed in relation to the mechanism of TMO reduction in E. coli.