retroglycosidase

Retroglycosidase is a theoretical enzyme that would catalyze the reverse of glycosidase activity. Glycosidases are enzymes that hydrolyze glycosidic bonds, breaking down carbohydrates. If a retroglycosidase existed, it would instead catalyze the formation of glycosidic bonds, effectively synthesizing complex carbohydrates from simpler sugars. This process is known as glycosylation.

The concept of retroglycosidases is primarily of theoretical interest in biochemistry and glycobiology. While glycosidases are well-characterized and abundant in nature, naturally occurring enzymes that catalyze the reverse reaction with high efficiency under physiological conditions are rare. The synthesis of complex carbohydrates in biological systems typically involves specific glycosyltransferases, which are distinct from glycosidases. These glycosyltransferases utilize activated sugar donors, such as nucleoside diphosphate sugars, to form glycosidic bonds.

However, some studies have explored the possibility of engineering glycosidases to perform glycosylation reactions. Under specific reaction conditions, such as high substrate concentrations or the removal of water, some glycosidases can be induced to catalyze the formation of glycosidic bonds, albeit often with low yields and forming undesired byproducts. This reverse hydrolysis activity is sometimes referred to as "transglycosylation" when a sugar moiety is transferred from one molecule to another, rather than direct synthesis from monosaccharides. The development of efficient and specific retroglycosidases or engineered glycosidases for carbohydrate synthesis remains an active area of research, with potential applications in areas like carbohydrate-based drug development and biomaterials.