Alkaline phosphatase (ALP) is an enzyme found in several kinds of tissues throughout the body. It is a hydrolase enzyme responsible for removing phosphate groups from many types of molecules, including nucleotides, proteins, and alkaloids. The process of removing the phosphate group is called dephosphorylation. And, the enzyme is most effective in an alkaline environment. Alkaline phosphatase ( ALP ) is a predominant enzyme which plays a significant role in the breakdown of organic substances. It is predominantly present in liver and bones. Clinically significant elevated levels are seen in the presence of biliary tract obstruction and conditions involving increased bone turnover.It is interpreted usually with other components of liver function test.Most commonly it is ordered as apart of comprehensive metabolic panel.