Cyclomaltodextrin glucanotransferase (CGTase) (CGTase)

Cyclomaltodextrin glucanotransferase (CGTase) is a bacterial enzyme belonging to the glycoside hydrolase family 13 (GH13), primarily responsible for the conversion of starch and other alpha-1,4-glucans into cyclic oligosaccharides known as cyclodextrins [1, 7]. Secreted extracellularly by various microorganisms, particularly within the genus Bacillus, the enzyme facilitates a unique intramolecular transglycosylation (cyclization) reaction that allows bacteria to utilize starch in a form less accessible to competitors [11, 12]. Although CGTase is not considered a direct therapeutic target for human disease, it is of critical importance to the pharmaceutical industry as the primary biocatalyst used to produce alpha-, beta-, and gamma-cyclodextrins [10, 13]. These cyclic products serve as vital pharmaceutical excipients that encapsulate hydrophobic drug molecules to enhance their solubility, stability, and bioavailability [7, 13]. Research has identified the anti-diabetic drug acarbose as a potent competitive inhibitor of CGTase, acting as a transition-state analog that binds to its active site in experimental settings [14]. While its role is predominantly industrial and biotechnological, the enzyme remains a significant subject of study in carbohydrate enzymology and drug delivery formulation [12, 14].

Other names

Cyclodextrin glucanotransferaseCyclodextrin glycosyltransferaseBacillus macerans amylaseBMACyclomaltodextrin glucanyltransferase1,4-alpha-D-glucan 4-alpha-D-(1,4-alpha-D-glucano)-transferase (cyclizing)Neutral-cyclodextrin glycosyltransferase

Competitive inhibition of the enzyme's active site by transition-state analogs (such as acarbose), which prevents the binding of starch substrates and halts the cyclization and transglycosylation reactions.