title: NAD+ glycohydrolase, an ecto-enzyme of calf spleen cells.
abstract: By using a sensitive fluorimetric assay of NAD+ glycohydrolase (EC 3.2.2.6), we showed that calf spleen cells are able to hydrolyse 1,N6-etheno-NAD+ given in the medium. The observed rates of substrate hydrolysis and product accumulation in the medium are equivalent. Moreover, the splenocytes are able to cleave the nicotinamide-ribose bond of a water-soluble polymer of NAD+, and their NAD+ glycohydrolase activity is fully inhibited by a high-molecular-weight Blue Dextran. Selective permeation of the cellular membrane digitonin revealed an intracellular pool of NAD+ glycohydrolase, which accounts for 25% of the total activity. We conclude that NAD+ glycohydrolase associated with the splenocytes has the characteristics of an ecto-enzyme.
mesh_terms: D000818:Animals; D002417:Cattle; D002463:Cell Membrane Permeability / Q000187:drug effects; D003911:Dextrans / Q000494:pharmacology; D004072:Digitonin / Q000494:pharmacology; D006868:Hydrolysis; D066298:In Vitro Techniques; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D009699:N-Glycosyl Hydrolases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D009244:NAD+ Nucleosidase; D013154:Spleen / Q000166:cytology / Q000187:drug effects / Q000201:enzymology*
chemical_list: D003911:Dextrans; C017080:blue dextran; D007770:L-Lactate Dehydrogenase; D009699:N-Glycosyl Hydrolases; D009244:NAD+ Nucleosidase; D004072:Digitonin