Aspartate Transaminase (AST) is an enzyme found in various tissues, including the liver, heart, and muscles. It plays a crucial role in amino acid metabolism by facilitating the transfer of an amino group from aspartate to α-ketoglutarate, producing oxaloacetate and glutamate. AST is commonly measured in blood tests to assess liver function and diagnose liver diseases, such as hepatitis or cirrhosis. Elevated levels of AST can indicate tissue damage, but it is important to interpret results alongside other tests, as high levels may also arise from conditions affecting the heart or muscles.