FIG. 4.

Initial velocity (V) of 4-COBE reduction by the wild-type and mutant ARIIs. Symbols: ●, wild type; ■, G₁₉→A mutant; □, G₂₂→A mutant; ○, A₂₅→G mutant. (A) Experiments performed with NADPH as a cofactor. (B) Experiments performed with NADH as a cofactor.