ASTcatalyzed

ASTcatalyzed refers to chemical reactions catalyzed by the enzyme aspartate aminotransferase (AST). AST is a pyridoxal phosphate–dependent transaminase that transfers amino groups between aspartate and 2-oxoglutarate to form oxaloacetate and glutamate. The enzyme is commonly classified as EC 2.6.1.1 and is also known as glutamate-oxaloacetate transaminase (GOT).

In the canonical reaction, L-aspartate and 2-oxoglutarate undergo transamination to yield oxaloacetate and L-glutamate. The reaction is reversible and proceeds via a ping-pong bi-bi mechanism in which the cofactor pyridoxal phosphate (PLP) forms a Schiff base with the enzyme, facilitates the transfer of the amino group, and is regenerated at the end of the catalytic cycle.

In humans, AST exists in two main isoforms: GOT1, the cytosolic form, and GOT2, the mitochondrial form. Both participate in amino acid metabolism and the malate-aspartate shuttle, a system that transfers reducing equivalents across cellular membranes and supports energy production and biosynthesis.

Clinical and research relevance: Serum AST levels rise with tissue damage but are not specific to the liver, so AST measurements are interpreted together with ALT in liver-function testing. AST activity also features in studies of nitrogen metabolism, amino-acid interconversion, and energy balance, and can be influenced by vitamin B6 status and subcellular localization.

Summary: AST-catalyzed transaminations link amino acid and keto-acid pools, enabling transfer of amino groups, supporting nitrogen metabolism, energy production, and integrated metabolic networks.