Glucose 6-phosphate dehydrogenase is an NADP-dependent enzyme that converts glucose 6-phosphate to 6-phosphogluconolactone. The later is then hydrolysed by the glucanolactone hydrolase to 6-phosphogluconate. The next reaction involving the synthesis of NADPH is catalysed by 6-phosphogluconate dehydrogenase to produce 3-keto 6-phosphogluconate, which then undergoes decarboxylation to give ribulose 5-phosphate.