ADP-ribosyl cyclase explained

NAD(P)+ nucleosidase
Ec Number:	3.2.2.6
Cas Number:	9025-46-1
Go Code:	0050135
Width:	270
ADP-ribosyl cyclase/cyclic ADP-ribose hydrolase

In enzymology, a ADP-ribosyl cyclase/cyclic ADP-ribose hydrolase is a bifunctional enzyme that catalyzes the chemical reaction

NAD⁺ + H₂O

\rightleftharpoons cADPR + H₂O + nicotinamide \rightleftharpoons ADP-ribose + nicotinamide

The 3 substrates of this enzyme are NAD⁺ and H₂O, whereas its two products are ADP-ribose and nicotinamide. The reaction proceeds through cyclic ADP-ribose (cADPR) as intermediate, which is then hydrolyzed into ADP-ribose. This makes it different from NAD⁺ glycohydrolase (EC 3.2.2.5), where the reaction does not proceed through cADPR.^{[1] [2]}

This enzyme belongs to the family of hydrolases, specifically those glycosylases that hydrolyse N-glycosyl compounds. Other names of this enzyme in common use include nicotinamide adenine dinucleotide (phosphate) nucleosidase, triphosphopyridine nucleotidase, NAD(P) nucleosidase, NAD(P)ase, and nicotinamide adenine dinucleotide (phosphate) glycohydrolase. This enzyme participates in nicotinate and nicotinamide metabolism.

References

• ALIVISATOS SG, WOOLLEY DW . 1956 . Solubilization and purification of the diphosphopyridine nucleotidase from beef spleen . J. Biol. Chem. . 219 . 823 - 32 . 13319302 . 2 .
• ZATMAN LJ, KAPLAN NO, COLOWICK SP . 1953 . Inhibition of spleen diphosphopyridine nucleotidase by nicotinamide, an exchange reaction . J. Biol. Chem. . 200 . 197 - 212 . 13034774 . 1 .
• Zatman LJ, Kaplan NO, Colowick SP, Ciotti MM . 1953 . Formation of the isonicotinic acid hydrazide analog of DPN . J. Am. Chem. Soc. . 75 . 13 . 3293 - 3294 . 10.1021/ja01109a527 .

Notes and References

1. Web site: ENZYME - 3.2.2.5 NAD(+) glycohydrolase . 2022-07-11 . enzyme.expasy.org.
2. Web site: ENZYME - 3.2.2.6 ADP-ribosyl cyclase/cyclic ADP-ribose hydrolase . 2022-07-11 . enzyme.expasy.org.