branched-chain-amino-acid transaminase activity

Definition

Target type: molecularfunction

Catalysis of the reaction: a branched-chain amino acid + 2-oxoglutarate = L-glutamate + a 2-oxocarboxylate derived from the branched-chain amino acid. [EC:2.6.1.42, GOC:mah]

Branched-chain amino acid transaminase (BCAT) activity is a crucial enzymatic function in the metabolism of branched-chain amino acids (BCAAs), namely leucine, isoleucine, and valine. These amino acids are essential for protein synthesis and various metabolic processes. BCAT catalyzes the reversible transfer of an amino group from a BCAA to an α-keto acid, typically α-ketoglutarate, resulting in the formation of an α-keto acid corresponding to the BCAA and glutamate. This reaction is a key step in the catabolism of BCAAs, facilitating their breakdown into energy-yielding molecules. The α-keto acids generated through BCAT activity then enter the tricarboxylic acid (TCA) cycle, where they are further oxidized to produce ATP. Additionally, BCAT plays a significant role in the biosynthesis of certain neurotransmitters, such as GABA, and in the regulation of cellular redox balance. The enzyme exists in two isoforms, BCAT1 and BCAT2, with distinct tissue distributions and regulatory mechanisms. BCAT1 is mainly expressed in skeletal muscle, while BCAT2 is found in the liver, brain, and other tissues. The activity of BCAT is influenced by various factors, including hormonal signals, nutritional status, and cellular energy demands. Dysregulation of BCAT activity can lead to metabolic disorders, such as maple syrup urine disease (MSUD), and can be implicated in neurological and cardiovascular diseases.'
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Proteins (1)

Compounds (1)