(fos′fă-tās″)

[phosphate + -ase]
One of a group of enzymes that catalyze the hydrolysis of phosphoric acid esters. They are important in the absorption and metabolism of carbohydrates, nucleotides, and phospholipids and are essential in the calcification of bone.

acid phosphatase

ABBR: ACP A phosphatase whose optimum pH is between 4.0 and 5.4. It is present in kidney, semen, serum, and prostate gland, and particularly in osteoclasts or odontoclasts in which it is associated with demineralization or resorption of bone and teeth.

alkaline phosphatase

ABBR: ALP An enzyme whose optimal pH is about 9.8. It is present in the liver, kidneys, intestines, teeth, plasma, and developing bone. Alkaline phosphatase levels greater than 300% of normal usually signify cholestatic disorders like obstructive jaundice or intrahepatic biliary disease.

CDc25 phosphatase

A group of intracellular enzymes that regulate cell division, some of which may contribute to the conversion of normal cells to cancer cells.

placental alkaline phosphatase

ABBR: PLAP A form of heat-stable alkaline phosphatase released by trophoblast cells in the human placenta, i.e., during pregnancy. Cancers of colon, lung, ovary, and testes, esp. seminoma, produce the enzyme ectopically.