SDS-PAGE of protein profiles of cell extracts (a) and purified protein preparations (b) from wild-type and mutant AzoA of Ent. faecalis expressed in E. coli. Lanes: M, protein molecular mass standards; 1, wild-type; 2, W105Y; 3, W105Q; 4, W105F; 5, W105H; 6, W105A; 7, W105G; and 8, wild-type. Extracts in lanes 1–7 were induced with IPTG; extract in lane 8 was not induced with IPTG.