Alpha14glucosidase

Alpha-1,4-glucosidase, sometimes written as Alpha14glucosidase in informal usage, is an enzyme that catalyzes the hydrolysis of terminal alpha-1,4-linked glucose residues from non-reducing ends of oligosaccharides, releasing free glucose. In humans it exists in multiple isoforms reflecting different cellular contexts: a lysosomal form called acid alpha-glucosidase (GAA) that digests glycogen within lysosomes, and brush-border forms associated with the sucrase-isomaltase and maltase-glucoamylase complexes that participate in dietary carbohydrate digestion.

Substrate range and mechanism: The enzyme acts on alpha-1,4 glycosidic bonds in maltose, maltotriose, and longer maltooligosaccharides, producing glucose. Most alpha-glucosidases belong to glycoside hydrolase family 13 and operate via a retaining double-displacement mechanism with two catalytic carboxylates, typically aspartate and glutamate residues.

Physiological and clinical significance: Digestive alpha-glucosidases enable efficient breakdown of starch-derived carbohydrates for absorption. Genetic deficiency or inhibition of specific forms can lead to carbohydrate malabsorption. Deficiency of lysosomal acid alpha-glucosidase causes Pompe disease (glycogen storage disease type II). Inhibitors of intestinal alpha-glucosidases, such as acarbose and miglitol, slow carbohydrate digestion and are used as therapies for type 2 diabetes; they can cause gastrointestinal side effects.

Classification and context: EC number 3.2.1.20; the enzyme is found across bacteria, fungi, plants, and animals, with human forms playing roles in digestion and glycogen breakdown. Ongoing research explores enzyme engineering for industrial glucose production and as therapeutic targets in metabolic disorders.