1.11.1.1 FAD - 1.11.1.1 FAD FAD-flavoprotein, 1 mol FAD per 1 mol enzyme 1.11.1.1 FAD enzyme contains flavin and non-flavin redox centers 1.11.1.1 FAD 2 mol flavin and 1 mol of a non-flavin electron acceptor at the active site 1.11.1.1 FAD flavoprotein. The resonance Raman (RR) modes of the oxidized and twoelectron reduced (EH2) forms of Npx are related to very tight flavin-protein interactions maintaining a nearly planar conformation of the isoalloxazine tricycle, a low level of H-bonding at the N1/N5 and O2/O4 sites, and a strong H-bond at N3H. Minimal changes in FAD structure and environment upon either NAD(H) binding or reduction of the sulfinic redox center 1.11.1.1 rubredoxin rubredoxin-like Fe(SCys)4-domain