Unusual enzymatic hydrolysis of NAD by solubilized form of NAD(+) glycohydrolase.
Using solubilized form (sNADase) of membrane-bound porcine brain NAD(+) glycohydrolase (pNADase), the NADase-catalyzed hydrolysis and transglycosidation reactions of NAD (1) were examined. Unexpectedly, products in the reactions were found to be nicotinamide (5'-O-diphosphono)-beta-D-ribofuranoside (4) and adenosine (5). Adenosine 5'-diphosphate (ADP)-ribose (2) and nicotinamide (3) as well as a transglycosylated product, which are formed in a usual NAD/pNADase reaction system, were scarcely produced in the NAD/sNADase system. Setting aside the mechanical aspects of this unusual cleaving, it is quite interesting that the sNADase-catalyzed hydrolytic reaction of NAD resulted in the selective cleavage of the P-O bond of the adenosine side without the appreciable hydrolysis of the labile quaternary nicotinamide-ribose pyridinium linkage.
Tono-oka
Shuichi
S
Division of Molecular Oncology, Institute for Genetic Medicine, Hokkaido University, Sapporo, Japan. tonny@imm.hokudai.ac.jp
Hatakeyama
Masanori
M
D000818:Animals; D001921:Brain / Q000201:enzymology; D006868:Hydrolysis; D009243:NAD / Q000378:metabolism*; D009244:NAD+ Nucleosidase / Q000378:metabolism*; D012995:Solubility; D013552:Swine
D009243:NAD; D009244:NAD+ Nucleosidase