Alkaline phosphatase

Alkaline phosphatase is a family of enzymes that removes phosphate groups from molecules most effectively in alkaline conditions. Its activity is especially prominent in the liver, bile ducts, and bones.

Hydrolysis: A chemical reaction that breaks a bond through the addition of water. Alkaline phosphatase uses water to cleave phosphate groups from substrates.
Alkaline phosphatase test: A blood test that measures alkaline phosphatase activity in serum or plasma. It is the routine clinical measurement of the enzyme described here.
Isoenzyme: One of several molecular forms of an enzyme that catalyze the same reaction but differ in structure or properties. Distinct tissue-associated forms account for alkaline phosphatase activity from multiple organs.
Tissue-nonspecific alkaline phosphatase: An alkaline phosphatase form expressed mainly in liver, bone, and kidney. This isoenzyme accounts for much of the activity in the three tissues emphasized here.
Phosphomonoesterase: An enzyme that hydrolyzes phosphate monoester bonds, releasing inorganic phosphate. Alkaline phosphatase belongs to this broader enzyme class.
Liver function tests: Blood tests used to assess liver injury, bile flow, and related functions. Alkaline phosphatase is interpreted alongside other markers of liver and bile-duct disease.
Liver: An organ that processes nutrients, produces bile, and performs many metabolic functions. The liver is a major source of circulating alkaline phosphatase.
Intestinal alkaline phosphatase: An alkaline phosphatase isoenzyme produced primarily by cells lining the intestine. It is a distinct tissue form within the same enzyme family.
Active site: The region of an enzyme where substrates bind and chemical reactions occur. Metal ions and substrate interactions at this site enable phosphate cleavage.
Gamma-glutamyl transferase: An enzyme measured in blood that can help identify hepatobiliary sources of elevated alkaline phosphatase. Its elevation alongside alkaline phosphatase supports a liver or bile-duct origin.

Linked from 11 pages