Glucose-6-phosphate dehydrogenase assay

G6PD activity was determined by monitoring NADPH production at 340 nm and 37 °C (27). The assay mixture contained 10 mmol/L MgCl₂, 0.2 mmol/L NADP⁺ and 0.6 mmol/L G6P in 100 mmol/L Tris/HCl buffer, pH 8.0. Assays were performed in duplicate and activities were followed for 60 s. The reaction was linear during that time. One unit (U) of activity is the amount of G6PD required to reduce one μmol of NADP⁺ per min under the assay conditions.