glykosidázy

Glykosidázy, known in English as glycosidases, are enzymes that catalyze the hydrolysis of glycosidic bonds in carbohydrates and glycosides. They are a diverse group of enzymes grouped under the umbrella of glycoside hydrolases (EC 3.2.x.x) and are found in many organisms, including humans, plants, and microbes. Their substrates range from simple disaccharides such as sucrose and lactose to complex polysaccharides like starch, glycogen, cellulose, and glycosaminoglycans, as well as glycoproteins and glycolipids.

Glycosidases are broadly categorized by the specific glycosidic bond they cleave and the type of sugar residue involved. They include alpha- and beta-glycosidases, exoglycosidases that remove one sugar at a time from the chain ends, and endoglycosidases that cut within the chain. Many play critical roles in digestion (for example, lactase, sucrase, and maltase in the intestinal brush border), while others function intracellularly in lysosomes or in cellular remodeling processes.

Mechanistically, glycosidases operate via retaining or inverting mechanisms, often using two key catalytic residues that act as acid/base and nucleophile, with some requiring metal ions for activity. Structural diversity is reflected in multiple protein folds and numerous CAZy glycoside hydrolase families.

Physiological and practical relevance is wide: deficiencies in specific lysosomal glycosidases cause storage diseases (such as Gaucher or Pompe disease); glycosidases are targets for therapies and diagnostics; in industry, microbial glycosidases enable biomass conversion and the processing of dairy and other carbohydrate-containing products.

In sum, glykosidázy encompass a essential and diverse class of enzymes central to carbohydrate metabolism, cellular function, and biotechnological applications.