Topic summary
Transamination
Transamination is a chemical reaction that transfers an amino group from an amino acid to an α-keto acid.
This process mainly takes place in the liver. In the liver, amino groups from different amino acids are transferred to α-ketoglutarate to form glutamate. In the mitochondria, glutamate is deaminated and toxic ammonium enters the urea cycle for excretion. Another site of transamination is the skeletal muscles. In the skeletal muscles, amino groups are transferred to pyruvate, forming alanine. Alanine carries nitrogen to the liver through the glucose–alanine cycle.
In biochemistry, the process occurs extensively during amino acid synthesis and is catalyzed by transaminases (aminotransferases), which requires the cofactor pyridoxal phosphate (PLP), and an α-keto acid as the acceptor of the amino group. α-ketoglutarate acts as the predominant amino-group acceptor and produces glutamate.
- Amino acid + α-ketoglutarate ↔ α-keto acid + glutamate
Glutamate's amino group, in turn, is transferred to oxaloacetate in a second transamination reaction yielding aspartate.