Aminotransferázs

Aminotransferases, also known as transaminases, are a class of enzymes that catalyze the transfer of an amino group from an amino acid to a keto acid. This process is fundamental to amino acid metabolism, playing a crucial role in both the synthesis and degradation of amino acids. They are ubiquitous in biological systems, found in all living organisms, from bacteria to humans.

The general reaction catalyzed by aminotransferases involves a coenzyme, pyridoxal phosphate (PLP), which is derived from vitamin B6. PLP binds to the enzyme and facilitates the transfer of the amino group through a series of intermediate steps. The amino acid loses its amino group to PLP, forming a keto acid and pyridoxamine phosphate (PMP). PMP then transfers the amino group to a keto acid, regenerating PLP and forming a new amino acid.

Aminotransferases are essential for various physiological processes. They are involved in the synthesis of non-essential amino acids, allowing the body to produce amino acids it cannot obtain from its diet. They also play a part in the breakdown of excess amino acids, converting them into intermediates that can enter energy-producing metabolic pathways or be converted into glucose or fatty acids.

In clinical diagnostics, serum levels of certain aminotransferases are used as biomarkers for tissue damage. For instance, elevated levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in the blood are indicative of liver injury, such as hepatitis or cirrhosis. Similarly, creatine kinase (CK), which has some aminotransferase activity, is used to detect muscle damage.