Abstract
The properties of thiamine diphosphatase (TDPase) and p-nitrophenylphosphatase (p-NPPase) in rat small intestine were investigated. TDPase activity, like p-NPPase activity, was high in the mucosa and in the proximal region. Both activities were high in the membrane-associated fractions of the duodenal mucosa. Furthermore, TDPase had the same properties as intestinal alkaline phosphatase (al-Pase). These results suggest that thiamine diphosphate (TDP) and p-nitrophenylphosphate (p-NPP) are hydrolyzed by a single enzyme, al-Pase, in the intestine.
MeSH terms
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4-Nitrophenylphosphatase / metabolism
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Animals
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Cations, Divalent / pharmacology
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Cyanides / pharmacology
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Edetic Acid / pharmacology
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Enzyme Inhibitors / pharmacology
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Hydrogen-Ion Concentration
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Intestinal Mucosa / enzymology
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Intestine, Small / enzymology*
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Kinetics
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Male
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Pyrophosphatases / metabolism*
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Rats
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Subcellular Fractions / enzymology
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Substrate Specificity
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Sulfhydryl Reagents / pharmacology
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Thiamine Pyrophosphatase / metabolism*
Substances
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Cations, Divalent
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Cyanides
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Enzyme Inhibitors
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Sulfhydryl Reagents
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Edetic Acid
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4-Nitrophenylphosphatase
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Pyrophosphatases
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Thiamine Pyrophosphatase