Phosphatase


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Related to Phosphatase: alkaline phosphatase, acid phosphatase

phosphatase

[′fäs·fə‚tās]
(biochemistry)
An enzyme that catalyzes the hydrolysis and synthesis of phosphoric acid esters and the transfer of phosphate groups from phosphoric acid to other compounds.

Phosphatase

 

any of the enzymes of the hydrolase class that catalyze the hydrolysis of phosphoric acid esters in animals, plants, and microorganisms. Phosphatases maintain the phosphate level necessary for various biochemical processes; it may be that they also transport phosphate to the cell.

Depending on the chemical nature of the substrate, phosphatases are divided into monophosphatases, for example, glucose 6-phosphatase, which hydrolyze monoesters of phosphoric acid, and diphosphatases, such as nucleases, which break down the diesters of phosphoric acid. Monophosphatases, in turn, are classified as either specific (interacting with only one substrate) or nonspecific (having a wide range of activity). Depending on the nature of the medium in which their maximum activity is observed, nonspecific monophosphatases are referred to as either alkaline (optimal activity at pH 8–10) or acid (pH 4–6). Alkaline phosphatases are found in animal tissue (intestinal mucosa, placenta, kidneys, bones) and in milk, bacteria, and fungi; acid phosphatases are present in the tissue of the prostate gland, spleen, and liver and in yeasts, bacteria, and higher plants.

The most comprehensive studies have been carried out on the structure and mechanism of activity of the alkaline phosphatase in Escherichia coli. The enzyme is composed of two identical sub-units that function alternately; it contains firmly bonded Zn atoms and has a molecular weight of 80,000. The arrangement of the polypeptide chains is known, and it has been established that the reaction with the substrate passes through a stage of enzyme phosphorylation. A determination of the activity of acid and alkaline phosphatases is important in diagnosing diseases, such as rickets, that are accompanied by an increase in phosphatase activity.

REFERENCES

The Enzymes, 3rd ed., vol. 4. New York-London, 1971.

S. M. AVAEVA

References in periodicals archive ?
Avian multiple inositol polyphosphate phosphatase is an active phytase that can be engineered to help ameliorate the planet's "phosphate crisis".
The purified rEcPP5 showed phosphatase activity towards pNPP (p-nitrophenyl phosphate) and phosphopeptides.
Quantification of liver alkaline phosphatase isoenzyme activity using heat inactivation and phenylalanine inhibition techniques: Comparison of two methods.
Acid phosphatase activity is known to contribute to resistance under salt and water stress by preserving a certain level of inorganic phosphate (Dubey and Sharma, 1990; Olmos and Hellin, 1997).
The report provides a snapshot of the global therapeutic landscape for Alkaline Phosphatase (ALKP or Phosphomonoesterase or Glycerophosphatase or Alkaline Phosphohydrolase or EC 3.
Alkaline phosphatase (ALP) is an ecto-enzyme in humans, which is attached through phosphatidyl inositol to the outer face of the plasma membrane.
Characterization of hematopoietic intracellular protein tyrosine phosphatases: Description of a phosphatase containing an SH2 domain and another enriched in proline-, glutamic acid-, serine-, and threonine-rich sequences.
Various studies have reported a negative effect of phosphorus fertilization on alkaline phosphatase (Kandeler et al.
The present study was conducted to evaluate the effect of buctril super herbicide on soil bacteria, fungi and actinomycetes population and also on soil urease, dehydrogenase and alkaline phosphatase activity.
6% increase in lumbar spine volumetric bone mineral density at the end of the study and an average 16% increase in bone alkaline phosphatase in comparison with the placebo group at each time point measured.
Dr Tony Holder, Head of the MRC-NIMR Division of Parasitology, said that inhibitors of protein kinases are already used in treatments for other diseases and there is growing interest to develop phosphatase inhibitors as drugs and once the key kinases and phosphatases in the parasite life cycle are identified it will define the targets for drug development to treat human malaria and prevent its transmission in communities by the mosquito.