ABSTRACT:

Alkaline phosphatase (ALP) is a family of isoenzymes, settled on the exterior of the cellular membrane; these enzymes stimulate the hydrolysis of phosphate esters found in the extracellular space. Zinc and magnesium are important co-factors for the biochemical function of alkaline phosphatases. It is estimated that over 80% of the ALPs in sera are supplied by hepatic tissue and bone and in a lower amount from the gut. Although alkaline phosphatases are present in various tissues throughout the body, their specific physiological role is still not well understood. This large family of dimeric enzymes is classified into four isozymes based on the tissue in which they are expressed, these include: tissue nonspecific alkaline phosphatase or liver/bone/kidney ALP, Germ cell ALP, Placental ALP, and Intestinal ALP. The liver is the major supplier of ALP, which is account for most elevation of this enzyme.
The next likely factor is heightened osteoblast activity, commonly seen in bone disorders or during growth phases. Additionally, in the late third trimester of pregnancy, the increase in placental ALP significantly raises levels in expectant mothers.

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