nonglycosidic

Nonglycosidic is an adjective used in biochemistry and glycobiology to denote a bond, linkage, or interaction that does not involve a glycosidic bond. Glycosidic bonds connect a sugar unit to another sugar or to a non-sugar moiety (the aglycone) as part of a glycoside or glycoconjugate. Nonglycosidic is used to describe any covalent attachment or noncovalent interaction involving a carbohydrate that is not formed by glycosidic chemistry, as well as processes that do not cleave glycosidic bonds.

In carbohydrate-related chemistry and enzymology, nonglycosidic terms are used when discussing reactions or structures where the sugar portion participates in bonds other than glycosidic linkages. Examples include ester, ether, amide, or phosphodiester bonds formed with carbohydrate-derived substrates that do not involve a glycosidic connection, or noncovalent interactions such as hydrogen bonding and ionic interactions between sugars and proteins or lipids. In contrast, glycosidic bonds are the primary covalent linkages of sugars in disaccharides, polysaccharides, and most glycoconjugates.

The term is relatively uncommon and its precise meaning is context-dependent; clarifying the specific type of bond or interaction is often necessary in scientific writing.

See also: glycosidic bond; glycoside; glycoconjugate; carbohydrate chemistry; enzyme specificity.