title: Rat intestinal nucleotide-sugar pyrophosphatase. Localization, partial purification, and substrate specificity.
abstract: The nucleotide-sugar pyrophosphatase activity of rat small intestine was studied using GDP-[14C]Man as substrate. The highest specific activities in the gastrointestinal tract were in the proximal small intestine, with a preferential localization in villus tip cells. Purified brush-border membranes were highly enriched in nucleotide-sugar pyrophosphatase. After the enzyme was solubilized with detergent and purified 180-fold, it hydrolyzed FAD and p-nitrophenyl-5'-thymidylate, as well as nucleotide sugars. That the same enzyme, a 5'-nucleotide phosphodiesterase, is responsible for nucleotide-sugar pyrophosphatase, phosphodiesterase I, and FAD pyrophosphatase activities is indicated by: co-migration in electrophoresis, parallel thermal inactivation, competitive inhibition studies, and similar regional, cellular, and subcellular localizations.
authors.forename: J C
authors.initials: JC
authors.lastname: Byrd
authors.forename: F J
authors.initials: FJ
authors.lastname: Fearney
authors.forename: Y S
authors.initials: YS
authors.lastname: Kim
mesh_terms: D000818:Animals; D003106:Colon / Q000201:enzymology*; D005753:Gastric Mucosa / Q000201:enzymology*; D007413:Intestinal Mucosa / Q000201:enzymology*; D007421:Intestine, Small / Q000201:enzymology*; D007700:Kinetics; D008297:Male; D008871:Microvilli / Q000201:enzymology; D009928:Organ Specificity; D011755:Pyrophosphatases / Q000302:isolation & purification* / Q000378:metabolism; D051381:Rats; D012995:Solubility; D013379:Substrate Specificity
chemical_list: D011755:Pyrophosphatases; C033324:nucleoside-diphosphosugar pyrophosphatase