Transaminase

Aminotransferases or transaminases are enzymes in all living things which the transfer of α -amino groups from a donor to an acceptor molecule catalyze ( transamination ). When laboratory testing for transaminases is the measurement of the blood values ​​for aspartate aminotransferase ( ASAT) and alanine aminotransferase ( ALAT ), have diagnostic significance in liver disease ( transaminases ).

Transaminases are essential in amino acid metabolism and the hexosamine biosynthesis. In addition, a glutamate -1 -semialdehyde aminotransferase in bacteria and archaea is involved in the porphyrin biosynthesis.

Catalyzed reaction

Usually it is in the donor to an amino acceptor, and in which an α -keto acid in which a new amino acid from the amino acid is a new α -keto and α -keto acid from the original. Pyridoxal phosphate as a cofactor involved in many cases.

Transaminases are available for 19 of the 20 proteinogenic amino acids, making these really are only conditionally essential. They can be converted from specific ketoacids, some of which are themselves not provided by metabolism. The partners amino acid is usually glutamate, which is deaminated to α -ketoglutarate and thus serves as a universal donor for amino groups. Therefore, glutamate is usually omitted in the designation of the transaminase.