phosphatase

Any of a group of enzymes (EC 3.1.3.x) that liberate orthophosphate from phosphoric esters. SEE ALSO: phosphohydrolases.

- acid p. a p. with an optimum pH of less than 7.0 (for several isozymes, it is 5.4), notably present in the prostate gland; demonstrable in lysosomes with Gomori nonspecific acid p. stain; it hydrolyzes many orthophosphoric monoesters.

- alkaline p. a p. with an optimum pH of above 7.0 ( e.g., 8.6), present ubiquitously; localized cytochemically in membranes by modifications of Gomori nonspecific alkaline p. stain; it hydrolyzes many orthophosphoric monoesters; low levels of this enzyme are seen in cases of hypophosphatasia.

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phos·pha·tase 'fäs-fə-.tās, -.tāz n an enzyme that accelerates the hydrolysis and synthesis of organic esters of phosphoric acid and the transfer of phosphate groups to other compounds:

a) ALKALINE PHOSPHATASE

b) ACID PHOSPHATASE

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n.

one of a group of enzymes capable of catalysing the hydrolysis of phosphoric acid esters. An example is glucose-6-phosphatase, which catalyses the hydrolysis of glucose-6-phosphate to glucose and phosphate. Phosphatases are important in the absorption and metabolism of carbohydrates, nucleotides, and phospholipids and are essential in the calcification of bone. Acid phosphatase is present in kidney, semen, serum, and the prostate gland. Alkaline phosphatase occurs in teeth, developing bone, plasma, kidney, and intestine.

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phos·pha·tase (fosґfə-tās) a term used in the recommended names of some enzymes of the hydrolase class that are phosphoric monoester hydrolases [EC 3.1.3], catalyzing the release of inorganic phosphate from phosphoric esters. See also acid phosphatase and alkaline phosphatase.