FIG. 4.

Time course of inhibition of lactaldehyde:propanediol oxidoreductase activity by Zn²⁺. His₆-FucO was incubated with 0.1 mM ZnCl₂ in the absence of FeSO₄ (○) or in the presence of 0.1 mM FeSO₄ (▴) or 1 mM FeSO₄ (▪). Control incubations in the absence of any metal were performed in parallel (•). At different times, aliquots were taken to measure the enzymatic activity following NADH oxidation using glycol aldehyde as the substrate.