Methylglyoxal reductase (NADPH-dependent)

Methylglyoxal reductase (NADPH-dependent), often abbreviated as MG reductase, is an enzyme that catalyzes the NADPH-dependent reduction of methylglyoxal to (S)-lactaldehyde. It belongs to the family of oxidoreductases, specifically those acting on the aldehyde or oxo group of donors with NAD+ or NADP+ as acceptor. The systematic name of this enzyme is S-2-hydroxypropanal:NADP+ oxidoreductase.

The primary biological role of methylglyoxal reductase is to detoxify methylglyoxal, a reactive dicarbonyl compound formed as a byproduct of glycolysis and other metabolic pathways. Methylglyoxal can react with proteins and DNA, leading to cellular damage and potentially contributing to various diseases.

The enzymatic reaction catalyzed by methylglyoxal reductase is:

Methylglyoxal + NADPH + H+ ⇌ (S)-lactaldehyde + NADP+

NADPH (nicotinamide adenine dinucleotide phosphate) serves as the reducing agent, providing the hydride ion necessary to reduce the carbonyl group of methylglyoxal. The (S)-lactaldehyde produced is then typically converted to other, less toxic metabolites, such as L-lactate, by other enzymes.

The enzyme is found in a wide range of organisms, including bacteria, fungi, plants, and animals. Its presence highlights the conserved importance of methylglyoxal detoxification across different forms of life. The structure and catalytic mechanism of methylglyoxal reductase have been extensively studied, providing insights into its function and potential as a target for therapeutic interventions in diseases linked to methylglyoxal accumulation. The regulation of its expression and activity can vary depending on the organism and cellular conditions.