Methanol dehydrogenase (nicotinoprotein)

Methanol dehydrogenase (nicotinoprotein), sometimes abbreviated as NAD-MDH, is an enzyme that catalyzes the oxidation of methanol to formaldehyde. It is a member of the oxidoreductase enzyme class and plays a crucial role in the metabolism of methanol in certain microorganisms, particularly some yeasts and bacteria. Unlike other methanol dehydrogenases that utilize pyrroloquinoline quinone (PQQ) as a cofactor, NAD-MDH employs nicotinamide adenine dinucleotide (NAD+) as its primary electron acceptor.

The general reaction catalyzed by methanol dehydrogenase (nicotinoprotein) is:

Methanol + NAD+ → Formaldehyde + NADH + H+

The NADH produced in this reaction can then be used in subsequent metabolic pathways to generate energy for the organism.

NAD-MDH enzymes typically consist of two or more subunits. The enzyme's structure varies depending on the source organism. These structural variations can influence the enzyme's substrate specificity and catalytic activity. The activity of NAD-MDH is often regulated by the availability of methanol and NAD+ and other environmental factors.

The enzyme is significant in biodegradation processes, particularly in environments where methanol is a significant carbon source. Its activity contributes to the removal of methanol from the environment and its conversion into less toxic compounds. The study of NAD-MDH can provide insights into microbial metabolism, enzyme structure-function relationships, and potential applications in bioremediation and biocatalysis.