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 ?
BMD and serum parameters includ-ing alkaline phosphatase, calcium and phosphate levels were carried out at postgraduate Physiology laboratory of University of Health Sciences, Lahore.
Characterization of the alkaline phosphatase expressed on the surface of a Hodgkin's lymphoma cell line.
Frederick Kiechle, MD, and colleagues reported that alkaline phosphatase levels, either alone or in conjunction with bilirubin levels, were not useful in determining the presence of common bile duct stones.
Macromolecular alkaline phosphatase and an immunoglobulin G that inhibited alkaline phosphatase in a patient's serum.
Primary antibodies included were rabbit IgG polyclonal antibody for Osteocalcin (catalogue number: PB9088, Boster Biological Technology, Pleasanton, US, at 1: 200 dilution) and rabbit polyclonal antibody to Alkaline Phosphatase (catalogue number: GTX100817, GeneTex International Corporation, Hsinchu City 300, Taiwan, at 1: 200 dilution).
Reference range and units 3/11/2017 3/12/2017 Alkaline Normal: 40-120 U/L 105 110 phosphatase ALT Normal: 10-45 U/L 404 347 AST Normal: 10-40 U/L 302 274 3/13/2017 3/15/2017 3/16/2017 4/25/2017 Alkaline 117 109 102 71 phosphatase ALT 356 363 331 349 AST 322 323 273 120 8/8/2017 Alkaline 79 phosphatase ALT 23 AST 17
Highest acid phosphatase activity was observed in case of oak canopy cover soil than the pine cover soil (Table 2).
NCTD is potent serine/threonine protein phosphatase 1 and protein phosphatase 2A (PP1 and PP2A) inhibitors.
Serum total alkaline phosphatase was found to be maximum in normal (N) group (159+- 7.61 U/l) and minimum in sub clinically hypothyroid (Sh) group (128+- 6.42 U/l).
The strains isolated from hand surfaces had the highest activity ofleucine arylamidase (an average of 14.3 nmol), acid phosphatase (an average of 13.7 nmol), and esterase (an average of 13.3 nmol), whereas the lowest activity was beta-glucuronidase (an average of 0.1 nmol); the isolates from mobile phone surfaces had the highest activity of esterase (an average of 15.0 nmol), leucine arylamidase (an average of 13.7 nmol), and esterase lipase (an average of 11.0 nmol), whereas the lowest activity was beta-glucuronidase (an average of 0.7 nmol).
Moss and King [11] reported the greater heat stability of liver phosphatase as compared with bone phosphatase.
Key words: Germination, seedling growth, salinity, acid phosphatase activity, Linum usitatissimum.