Leucine dehydrogenase

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Leucine dehydrogenase is an enzyme that catalyzes the oxidative deamination of L-leucine to α-ketoisocaproate and ammonia. This enzyme is a member of the oxidoreductase family, specifically those acting on the CH-NH2 group of donors with NAD+ or NADP+ as acceptors.

Function

Leucine dehydrogenase plays a crucial role in the metabolism of branched-chain amino acids, particularly leucine. It is involved in the catabolic pathway of leucine, facilitating its conversion into acetyl-CoA and acetoacetate, which are important intermediates in energy production and biosynthesis.

Structure

The enzyme typically functions as a homotetramer, with each subunit containing a binding site for the coenzyme NAD+. The active site of leucine dehydrogenase is highly specific for its substrate, L-leucine, and the reaction it catalyzes involves the removal of an amino group from leucine, resulting in the formation of α-ketoisocaproate.

Mechanism

The catalytic mechanism of leucine dehydrogenase involves the transfer of a hydride ion from the substrate to the NAD+ coenzyme, followed by the release of ammonia. This process is essential for the proper degradation of leucine and the subsequent utilization of its carbon skeleton in various metabolic pathways.

Applications

Leucine dehydrogenase has significant applications in biotechnology and clinical diagnostics. It is used in the enzymatic assays for the determination of leucine levels in biological samples. Additionally, it has potential applications in the production of chiral compounds and the biocatalysis of specific chemical reactions.

Related Enzymes

Leucine dehydrogenase is related to other amino acid dehydrogenases, such as glutamate dehydrogenase and alanine dehydrogenase, which also play roles in amino acid metabolism.

See Also

• Amino acid metabolism
• Branched-chain amino acids
• Oxidoreductase
• NAD+

External Links

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