To Estimate the Activity of Alkaline Phosphatase in Serum
Alkaline phosphatase (ALP) is a membrane-bound enzyme present mainly in the liver, bone, intestine, and placenta. ALP shows maximum activity at about pH 10. This enzyme is intracellular and only a small amount is present in plasma. In certain disease conditions, the breakdown of cell causes release of enzyme to plasma leading to increased enzyme levels in plasma. The ALP of normal serum in adults is mainly derived from the liver and bone and small amount from intestinal component. During childhood the majority of alkaline phosphatase is of skeletal origin. During pregnancy, ALP is also contributed from the placenta. ALP is activated by magnesium ions. The activity in serum is due to isoenzymes from various organs, but the major contribution occurs from the liver.