Transzamináz

Transzamináz is a group of enzymes that catalyze the transfer of an amino group from an alpha-amino acid to an alpha-keto acid. This process is known as transamination and is a crucial step in amino acid metabolism, particularly in the synthesis and degradation of amino acids. Transaminases are widely distributed in living organisms, playing vital roles in various physiological processes.

The reaction catalyzed by transaminases typically involves an amino donor, usually an amino acid, and an amino acceptor, an alpha-keto acid. The amino group is transferred from the donor to the acceptor, resulting in the formation of a new amino acid and a new alpha-keto acid. This reversible reaction allows for the interconversion of amino acids and alpha-keto acids, facilitating the production of non-essential amino acids and the catabolism of amino acids.

Many transaminases require pyridoxal phosphate (PLP), a derivative of vitamin B6, as a cofactor. PLP acts as an intermediate carrier of the amino group during the catalytic cycle. Different transaminases exhibit specificity for particular amino acid substrates and alpha-keto acid substrates.

In clinical diagnostics, the levels of certain transaminases in the blood can serve as indicators of tissue damage. For example, elevated levels of alanine transaminase (ALT) and aspartate transaminase (AST) are commonly measured to assess liver function. Damage to liver cells releases these enzymes into the bloodstream, leading to increased serum concentrations. Other transaminases, such as gamma-glutamyl transpeptidase (GGT), are also used in liver function tests.