alkaline phosphatase


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alkaline

 [al´kah-līn]
1. having the reactions of an alkali.
2. having a pH greater than 7.0.
alkaline phosphatase an enzyme localized on cell membranes that hydrolyzes phosphate esters liberating inorganic phosphate and has an optimal pH of about 10.0. Serum alkaline phosphatase activity is elevated in hepatobiliary disease, especially in obstructive jaundice, and in bone diseases with increased osteoblastic activity such as hyperparathyroidism, osteitis deformans, and bone cancer. The liver and bone tissue each produce a distinct isoenzyme.

phosphatase

 [fos´fah-tās]
any of a group of enzymes capable of catalyzing the hydrolysis of esterified phosphoric acid, with liberation of inorganic phosphate, found in practically all tissues, body fluids, and cells, including erythrocytes and leukocytes.
acid phosphatase see acid phosphatase.
alkaline phosphatase see alkaline phosphatase.

al·ka·line phos·pha·tase

a phosphatase with an optimal pH higher than 7, present ubiquitously; localized cytochemically in membranes by modifications of Gomori nonspecific alkaline phosphatase stain; it hydrolyzes many orthophosphoric monoesters; low levels of this enzyme are seen in cases of hypophosphatasia.

alkaline phosphatase

A 69-kD homodimeric metalloenzyme, EC 3.1.3.1, with broad specificity, which is widely distributed in nature, has an optimal activity at a high (± 10) pH, and occurs in multiple forms: isoenzymes in the liver, intestines and bone. Alkaline phosphatase (AP) hydrolyses phosphate esters, yielding alcohol and phosphate; because increased total AP indicates either liver or bone disease, additional clinical studies, such as evaluation of AP isoenzymes, are required to determine the cause of the elevation.
 
Physiologic increase in AP
During bone growth: infants’, children’s and adolescents’ levels are 3-fold > than adults; pregnancy.

Pathologic increase in AP
Hepatobiliary disease (e.g., viral hepatitis, severe biliary obstruction, biliary cirrhosis, intrahepatic cholestasis), Paget’s disease of bone, osteomalacia, osteogenic sarcoma, bone metastasis, hyperparathyroidism, infectious mononucleosis, vitamin D deficiency rickets.

Decreased AP
Hypoposphatasia, protein deficiency, magnesium deficiency.
 
Ref Range
AP ranges differ according to method and lab.

alkaline phosphatase

'Alk phos' Clinical chemistry A 69 kD homodimeric metalloenzyme with broad specificity, which is widely distributed in nature, has an optimal activity at a high–± 10 pH, and occurs in multiple forms–isoenzymes in the liver, intestines, and bone; AP hydrolyzes phosphate esters, yielding alcohol and phosphate; because ↑ total AP indicates either liver or bone disease, additional clinical studies–eg, evaluation of AP isoenzymes, are required to determine the cause of the elevation Physiologic ↑ in AP: During bone growth, infants, children and adolescents-levels are 3-fold > than adults, pregnancy, hepatobiliary disease–eg viral hepatitis, severe biliary obstruction, biliary cirrhosis, intrahepatic cholestasis, Paget's disease of bone, osteomalacia, osteogenic sarcoma, bone metastasis, hyperparathyroidism, infectious mononucleosis, vitamin D deficiency rickets; ↓ in hypoposphatasia, protein deficiency, magnesium deficiency Ref Range AP ranges differ according to method and lab. See Alkaline phosphatase isoenzyme, Immunoperoxidase.

al·ka·line phos·pha·tase

(al'kă-lin fos'fă-tās)
A phosphatase with an optimal pH of above 7.0 present in many tissues; low levels of this enzyme are seen in cases of hypophosphatasia.

Alkaline phosphatase

An enzyme found throughout the body, primarily in liver, bone, placenta, and intestine.

al·ka·line phos·pha·tase

(al'kă-lin fos'fă-tās)
A phosphatase with an optimal pH of above 7.0 present in many tissues; low levels of this enzyme are seen in cases of hypophosphatasia.
References in periodicals archive ?
The loss of BMD in osteopenic group was supported by the increased activity of alkaline phosphatase and significantly raised serum calcium levels in osteopenic group.
Pearl: AST and ALT elevations in patients with acute abdominal pain could be due to choledocholithiasis, even if there are minimal or no abnormalities in alkaline phosphatase. Marked elevations (greater than 1,000) can occur.
Low serum alkaline phosphatase activity associated with severe Wilson's disease.
Shen, "High serum alkaline phosphatase cooperating with MMP-9 predicts metastasis and poor prognosis in patients with primary osteosarcoma in Southern China," World Journal of Surgical Oncology, vol.
Serum alkaline phosphatase was negatively related with TSH in Sh and SH and positively related in the other groups.
Monoclonal antibody assay for measuring bone-specific alkaline phosphatase activity in serum.
Kalantar-Zadeh, "Towards the revival of alkaline phosphatase for the management of bone disease, mortality and hip fractures," Nephrology Dialysis Transplantation, vol.
Muhammad et al., "Intestinal alkaline phosphatase promotes gut bacterial growth by reducing the concentration of luminal nucleotide triphosphates," American Journal of Physiology--Gastrointestinal and Liver Physiology, vol.
Bone-forming cells have been shown to have alkaline phosphatase (ALP) activity and changes in this enzyme in serum and bone have been used as markers for bone metabolism in several diseases [45, 46].
In our study, 79% were in the insufficient range, 21% were in the deficient range with normal levels of serum alkaline phosphatase, and none were in the optimal level.
For blood group analysis, blood group anti sera were used, while for serum alkaline phosphatase, a chemistry analyser was used.

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