Hydrolyzes the gluconolactone formed by glucose-fructose oxidoreductase, and that formed in aerobic conditions by the glucose dehydrogenase present. D-glucono-1,5-lactone + H2O = D-gluconate + H(+) Carbohydrate acid metabolism; D-gluconate biosynthesis; D-gluconate from D-glucono-1,5-lactone: step 1/1. Homodimer. Predicted to be exported by the Tat system. The position of the signal peptide cleavage has been experimentally proven. It is possible that in some cases Met-40 is the initiator in this case the expressed enzyme would remain cytoplasmic.