Calf-spleen nicotinamide--adenine dinucleotide glycohydrolase. Solubilization purification and properties of the enzyme.
NAD glycohydrolase of calf spleen was solubilized with pancreatic lipase and purified approximatively 800-fold to a specific activity of 7 units/mg of protein by successive DEAE-cellulose and carboxymethyl-cellulose chromatography. The purified enzyme has a molecular weight of 24,000 and is characterized by a double band on disc gel electrophoresis. Some kinetic properties of the NAD-glycohydrolase-catalyzed hydrolsis of NAD have been examined using a titrimetric assay for enzyme activity. The reaction is subject to inhibition be excess of substrate, which disappears at high ionic strength and low pH. At a pH below 5 the kinetic displays an apparent activation by substrate. The effects of pH (4.5-9.0) on the kinetic parameters do not reveal an essential ionizable group in the catalytic process.
D000818:Animals; D002417:Cattle; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D009699:N-Glycosyl Hydrolases / Q000302:isolation & purification / Q000378:metabolism*; D009243:NAD / Q000494:pharmacology; D009994:Osmolar Concentration; D012995:Solubility; D013154:Spleen / Q000201:enzymology*
D009243:NAD; D009699:N-Glycosyl Hydrolases