Phosphatase

(redirected from Placental Alkaline Phosphatase)
Also found in: Dictionary, Thesaurus, Medical, Acronyms.
Related to Placental Alkaline Phosphatase: Leukocyte alkaline 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.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

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

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
References in periodicals archive ?
of Cases) Positive Negative Pancytokeratin (a) (11) 3/11 8/11 Vimentin (12) 12/12 0/12 EMA (9) 0/9 9/9 Inhibin (6) 5/6 1/6 SMA (4) 4/4 0/4 S100 (4) 2/4 2/4 PLAP (4) 0/4 4/4 Desmin (3) 2/3 1/3 MIC2 (013) (3) 3/3 0/3 LMW cytokeratin (2) 2/2 0/2 Calretinin (2) 2/2 0/2 ER/PR (1) 0/1 1/1 Chromogranin (1) 0/1 1/1 Synaptophysin (1) 0/1 1/1 c-kit (1) 0/1 1/1 CD30 (1) 0/1 1/1 [beta]-HCG (1) 0/1 1/1 LCA (2) 0/1 1/1 AFP (1) 0/1 1/1 Abbreviations: AFP, [alpha]-fetoprotein; [beta]-HCG, [beta] human chorionic gonad-otropin; EMA, epithelial membrane antigen; ER/PR, estrogen and progesterone receptor; LCA, leukocyte common antigen; LMW, low molecular weight;PLAP, placental alkaline phosphatase; SMA, smooth muscle actin.
TABLE I PLACENTAL ALKALINE PHOSPHATASE ACTIVITY VALUE AND INDICES OF FOETAL NUTRITION Analytes Mean [+ or -] SD (n = 105) Placental alkaline phosphatase (IU/L) 115.5 [+ or -] 5.3 Cord blood glucose (mmol/L) 3.9 [+ or -] 0.5 Cord blood albumin (g/L) 40.1 [+ or -] 6.2 Neonatal birth weight (kg) 3.3 [+ or -] 0.9 Gestational age at term (wk) 39.2 [+ or -] 1.0
(7) Spermatocytic seminoma lacks the features of classic seminoma including a fibrous stroma, lymphocytic and/or granulomatous stromal reaction, cells with abundant glycogen, positivity for placental alkaline phosphatase, and intratubular germ cell neoplasia component.
Enzyme amplification--a general method applied to provide an immunoassisted assay for placental alkaline phosphatase. J Immunol Methods 1985;76:389-93.
The antibodies used were specific for CD45RB (leukocyte common antigen; 1:300, Dako Corporation, Carpinteria, Calif), CD3 (1:150, Dako), CD20 (L26; 1:700, Dako), CD79a (1:50, Dako), [Kappa] immunoglobulin light chain (1:10000, Dako), [Lambda] immunoglobulin light chain (1:10000, Dako), Bcl-6 (1: 10, Dako), epithelial membrane antigen (1:25, Dako), CD10 (1:70, Vector, Burlingame, Calif), CD30 (1:20, Signet, Dedham, Mass), Bcl-2 (1:200, BioGenex, San Ramon, Calif), Ki-67 (1:20, Beckmann Coulter, Miami, Fla), keratin (AE1/AE3; 1:500, Boehringer Mannheim, Indianapolis, Ind), [Alpha]-fetoprotein (1:25, Zymed Lab, San Francisco, Calif), and placental alkaline phosphatase (1:20, Lab Vision Corp, Freemont, Calif).
The antibodies used included S100 protein (polyclonal), desmin (D33), carcinoembryonic antigen (polyclonal), chromogranin A, [Alpha]-1-fetoprotein (polyclonal), glial fibrillary acidic protein (GFAP, 6F2), and placental alkaline phosphatase (polyclonal; all from Dakopatts, Glostrup, Denmark); CD34 (QBend 10, Serotec, Washington, DC); pancytokeratin (AE1/AE3, Boehringer, Mannheim, Germany); [Alpha]-smooth muscle actin (1A4, Sigma, St Louis, Mo); muscle-specific actin (HHF-35, Enzo Diagnostic, New York, NY); CD99 (O13, Signet, Dedham, Mass), [Alpha]-inhibin (RI, Serotec, Oxford, England); estrogen receptor (ER1D5, Dakopatts), and progesterone receptor (PR10A9, Immunotech, Marseille, France).