MSI_000025633

Guanosine diphosphate mannose, also known as gdp-D-mannose or guanosine pyrophosphoric acid mannose, is a member of the class of compounds known as purine nucleotide sugars. Purine nucleotide sugars are purine nucleotides bound to a saccharide derivative through the terminal phosphate group. Guanosine diphosphate mannose is slightly soluble (in water) and a moderately acidic compound (based on its pKa). Guanosine diphosphate mannose can be found in a number of food items such as sorrel, common persimmon, citrus, and butternut, which makes guanosine diphosphate mannose a potential biomarker for the consumption of these food products. Guanosine diphosphate mannose exists in all living species, ranging from bacteria to humans. In humans, guanosine diphosphate mannose is involved in a couple of metabolic pathways, which include fructose and mannose degradation and fructose intolerance, hereditary. Guanosine diphosphate mannose is also involved in fructosuria, which is a metabolic disorder. Guanosine diphosphate mannose or GDP-mannose is a nucleotide sugar that is a substrate for glycosyltransferase reactions in metabolism. This compound is a substrate for enzymes called mannosyltransferases . GDP-mannose is a nucleoside diphosphate sugar that is important in the production of fucosylated oligosaccharides. In particular, GDP-mannose is converted to GDP-fucose, which is the fucose donor in the construction of all mammalian fucosylated glycans. GDP-mannose is transformed to GDP-fucose via three enzymatic reactions carried out by two proteins, GDP-mannose 4,6-dehydratase (GMD) and a second enzyme, GDP-keto-6-deoxymannose 3,5-epimerase, 4-reductase. GDP-mannose 4,6-dehydratase (EC 4.2.1.47) catalyzes the chemical reaction: GDP-mannose <--> GDP-4-dehydro-6-deoxy-D-mannose + H2O. The epimerase converts the GDP-4-dehydro-6-deoxy-D-mannose to GDP-fucose (PMID: 12651883). GDP-mannose is also synthesized from mannose 1-phosphate via the enzyme ATP-mannose-1-phosphate-guanyltransferase and GTP. Acquisition and generation of the data is financially supported in part by CREST/JST.