Mannosetoglucose

Mannosetoglucose is a term sometimes used to describe the relationship or potential interconversion between the monosaccharides mannose and glucose. Both sugars are aldohexoses with the same chemical formula, C6H12O6, and they differ at the second carbon, making them epimers.

Chemically, glucose and mannose can interconvert through common sugar‐chemistry processes. In solution, aldose sugars undergo mutarotation, and interconversion between configurations can occur via the open-chain form followed by reclosure. Such interconversion is typically slow in the absence of catalysts and is more readily described as a conceptual relationship than as a single, defined chemical reaction.

In biological systems, mannose is usually processed through phosphorylation to mannose-6-phosphate and then isomerized to fructose-6-phosphate by phosphomannose isomerase, feeding into glycolysis. There is no widely used direct enzymatic pathway that converts free mannose to free glucose; instead, mannose enters metabolism through intermediates that eventually connect to common central carbon pathways. Conceptually, the notion of "mannose to glucose" can appear in discussions of hexose interconversion or comparative metabolism, but it does not represent a standard pathway in most organisms.

Analytical identification of glucose versus mannose relies on chromatographic methods (such as high-performance liquid chromatography or gas chromatography) and spectroscopic techniques (including NMR and optical rotation), which distinguish stereochemistry at C-2 and other structural features.

See also: Glucose, Mannose, Epimer, Mutarotation, Phosphomannose isomerase, Hexose.