serineaspartate

Serine-aspartate, also known as serine-aspartate transaminase or simply AST, is an enzyme classified as a transaminase, which catalyzes the transfer of amino groups between amino acids and α-keto acids. It plays a crucial role in amino acid metabolism, particularly in the conversion of aspartate to oxaloacetate and α-ketoglutarate to glutamate. This process is essential for maintaining nitrogen balance and supporting cellular energy production through the tricarboxylic acid (TCA) cycle.

AST is primarily found in the liver, heart, skeletal muscle, kidneys, and brain, where it facilitates the transfer of amino groups during transamination reactions. The enzyme is a dimer, meaning it consists of two identical polypeptide chains, and its activity is tightly regulated to ensure proper metabolic function.

Serine-aspartate transaminase is often measured in clinical settings as part of liver function tests, alongside alanine aminotransferase (ALT). Elevated levels of AST in blood serum may indicate liver damage or disease, such as hepatitis, cirrhosis, or alcoholic liver disease. However, AST levels can also rise due to muscle injury, heart conditions, or other metabolic disturbances, making it a non-specific marker of tissue damage.

The enzyme’s activity depends on the presence of cofactors, including pyridoxal phosphate (PLP), a derivative of vitamin B6. Deficiencies in vitamin B6 can impair AST function, leading to metabolic imbalances. Research into serine-aspartate transaminase has contributed to understanding metabolic disorders, drug metabolism, and the biochemical basis of various diseases. Its role in amino acid metabolism continues to be an area of active study in biochemistry and medical research.