ADP-ribosyl cyclase EC:3.2.2.5 (also know as cyclic ADP-ribose hydrolase or CD38) synthesises cyclic-ADP ribose, a second messenger for glucose-induced insulin secretion.
ADP-ribosyl cyclase catalyses the elimination of nicotinamide from NAD and cyclisation of cADPR. It has been identified in many organisms from microbes to mammals. The product from this enzyme, cADPR, is a second messenger in cellular calcium signalling pathways and it regulates the concentration of calcium ions in a variety of mammalian and non-mammalian cell types.