amidohydrolase

Amidohydrolase refers to enzymes that catalyze the hydrolysis of amide bonds, converting amides into carboxylates and amines or ammonium. They play roles in nitrogen metabolism, detoxification, and the breakdown of amide-containing compounds in diverse organisms, including bacteria, archaea, and eukaryotes. The term covers a broad set of enzymes that share the chemical task of breaking amide linkages, though their substrates and precise mechanisms can vary widely.

Most amidohydrolases are metalloenzymes that use one or more metal ions in their active sites to activate a water molecule for nucleophilic attack on the amide carbonyl. Common metal cofactors include zinc, manganese, and iron. In many members of this family, a binuclear metal center coordinates the substrate and stabilizes reaction intermediates, while nearby residues shuttle protons to facilitate catalysis. Structural diversity exists, but a conserved theme is the reliance on metal-activated water to hydrolyze the amide bond.

Substrate scope for amidohydrolases is broad and includes simple carboxamides such as acetamide and other amide-containing compounds, including some drug metabolites and urea derivatives. They are distinct from proteases, which cleave peptide bonds within proteins, though both classes perform amide hydrolysis. Within the amidohydrolase landscape, the amidohydrolase superfamily comprises many enzymes sharing a common fold and metal-dependent mechanism.

Biological and practical significance of amidohydrolases includes roles in nitrogen recycling and detoxification, as well as applications in bioremediation and industrial biocatalysis. Their ability to operate under mild conditions and process diverse substrates makes them of interest for enzyme engineering and environmental biotechnology.