hydrolasesincluding

Hydrolases are a broad class of enzymes that catalyze hydrolysis reactions, cleaving chemical bonds with the addition of water. In the IUBMB enzyme nomenclature they are classified as EC class 3. Hydrolases participate in digestion, metabolism, and cellular turnover by breaking bonds such as esters, amides, glycosidic linkages, and phosphoester bonds.

Some of the best-known hydrolases include proteases, which cleave peptide bonds in proteins; lipases, which hydrolyze ester bonds in lipids; nucleases, which break down nucleic acids; glycosidases, which hydrolyze glycosidic bonds in carbohydrates; and phosphatases, which remove phosphate groups from substrates. Additional examples include esterases and amidases; ureases also participate in hydrolysis of urea. Hydrolases function in extracellular, intracellular, and lysosomal contexts.

Most hydrolases operate with a catalytic mechanism that uses active-site residues or metal ions to activate a water molecule that acts as a nucleophile. Serine hydrolases (such as many serine proteases) form a transient acyl-enzyme intermediate; cysteine- or aspartate-based hydrolases use alternate catalytic strategies. Metallohydrolases rely on coordinated metal ions, often zinc, to polarize water and facilitate bond cleavage.

Physiological roles are diverse: digestive hydrolases such as pancreatic proteases, amylase, and lipase aid nutrient breakdown; lysosomal acid hydrolases degrade macromolecules in the acidic cellular compartments. In medicine and industry, hydrolases serve as drug targets (for example, protease inhibitors in antiviral therapy) and as biocatalysts in synthesis, food processing, and environmental cleanup. Their activity is affected by pH, temperature, and inhibitors or activators; many hydrolases are studied for engineering improved stability and specificity.