Phosphatase

(redirected from PLAP)
Also found in: Dictionary, Thesaurus, Medical, Acronyms.
Related to PLAP: Plab, Play Store

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 ?
Further sections from all these tumours were stained with an array of IHC markers, PLAP, CD-117, OCT-4, CK, CD30 and AFP.
But PLAP expression is not a specific indicator of Dysgerminoma as other germ cell tumours and some carcinomas also express PLAP.
In our study, three out of nine cases were negative for PLAP and 2 cases showed only patchy staining for PLAP.
Another case of embryonal carcinoma was positive only for PLAP, which is contrary to what is expected.
This is the reason why PLAP was first introduced in the English Language Learning class before any other subject.
The study seeks to highlight the challenges faced by teachers in the implementation of PLAP with the aim of suggesting possible solutions to these challenges.
Form 3 teachers were also selected because the current form three students were the most affected by the 2006-2009 disturbances as they were in grades 2, 3, 4 and 5 hence it was expected that these children were in great need of PLAP.
Most of the teachers lamented the lack of time with which to implement PLAP.
173,175) Dysgerminoma and yolk sac tumor are positive for SALL4, and approximately half of yolk sac tumors show some staining with PLAP and CD117, as compared to the diffuse and strong staining in most dysgerminoma cases.
Similarly, clear cell carcinoma may focally express the commonly used dysgerminoma markers such as SALL4, OCT3/4, PLAP, and D2-40.
Ovarian Germ Cell Tumors Versus Ovarian Epithelial Tumors and Melanoma Marker DYSG YST EMBR CHORIO SEROUS SALL4 + + + + or - (a) - SOX2 + or - - + - + NANOG + - + - + D2-40 + - or f+ - - - PLAP + - or + + - or + + or - GP-3 - or + + - + - OCT4 + - + - - CD117 + + or - - or + - - or + AFP - + - or + - - hCG - or f+ - - or + + - CD30 - - + - - PAX8 - - - ?