What are transamination reactions and why are they important?

Transamination is the transfer of an amino group from an amino acid to an alpha-keto acid, producing a new amino acid and new keto acid. The reaction is catalyzed by aminotransferases (transaminases) using pyridoxal phosphate (PLP, vitamin B6) as a cofactor. For example, alanine aminotransferase (ALT) transfers amino groups between alanine and alpha-ketoglutarate, producing pyruvate and glutamate. Transamination is important for: amino acid synthesis (making non-essential amino acids), amino acid degradation (funneling nitrogen to glutamate for excretion), and connecting amino acid metabolism to carbohydrate metabolism. Elevated blood transaminases indicate liver damage.