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Guanosine diphosphate mannose or GDP-mannose is a
nucleotide sugar Nucleotide sugars are the activated forms of monosaccharides. Nucleotide sugars act as glycosyl donors in glycosylation reactions. Those reactions are catalyzed by a group of enzymes called glycosyltransferases. History The anabolism of oligosaccha ...
that is a substrate for
glycosyltransferase Glycosyltransferases (GTFs, Gtfs) are enzymes ( EC 2.4) that establish natural glycosidic linkages. They catalyze the transfer of saccharide moieties from an activated nucleotide sugar (also known as the "glycosyl donor") to a nucleophilic glycos ...
reactions in
metabolism Metabolism (, from el, μεταβολή ''metabolē'', "change") is the set of life-sustaining chemical reactions in organisms. The three main functions of metabolism are: the conversion of the energy in food to energy available to run cell ...
. This compound is a substrate for enzymes called
mannosyltransferase A mannosyltransferase is a type of glycosyltransferase that acts upon mannose Mannose is a sugar monomer of the aldohexose series of carbohydrates. It is a C-2 epimer of glucose. Mannose is important in human metabolism, especially in the glyco ...
s. Known as donor of activated mannose in all glycolytic reactions, GDP-mannose is essential in eukaryotes.


Biosynthesis

GDP-mannose is produced from GTP and
mannose-6-phosphate Mannose-6-phosphate (M6P) is a molecule bound by lectin in the immune system. M6P is converted to fructose 6-phosphate by mannose phosphate isomerase. M6P is a key targeting signal for acid hydrolase precursor proteins that are destined for transp ...
by the enzyme
mannose-1-phosphate guanylyltransferase In enzymology, a mannose-1-phosphate guanylyltransferase () is an enzyme that catalyzes the chemical reaction :GTP + alpha-D-mannose 1-phosphate \rightleftharpoons diphosphate + GDP-mannose Thus, the two substrates of this enzyme are GTP and ...
. One of the enzymes from the family of nucleootidyl-transferases, GDP-Mannose Pyrophosphorylase (GDP-MP) is an pervasive enzyme found in bacteria, fungi, plants, and animals.


References


See also

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Nucleoside Nucleosides are glycosylamines that can be thought of as nucleotides without a phosphate group. A nucleoside consists simply of a nucleobase (also termed a nitrogenous base) and a five-carbon sugar (ribose or 2'-deoxyribose) whereas a nucleotide ...
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Nucleotide Nucleotides are organic molecules consisting of a nucleoside and a phosphate. They serve as monomeric units of the nucleic acid polymers – deoxyribonucleic acid (DNA) and ribonucleic acid (RNA), both of which are essential biomolecules wi ...
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Guanosine Guanosine (symbol G or Guo) is a purine nucleoside comprising guanine attached to a ribose (ribofuranose) ring via a β-N9-glycosidic bond. Guanosine can be phosphorylated to become guanosine monophosphate (GMP), cyclic guanosine monophosphate (c ...
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Guanosine diphosphate Guanosine diphosphate, abbreviated GDP, is a nucleoside diphosphate. It is an ester of pyrophosphoric acid with the nucleoside guanosine. GDP consists of a pyrophosphate group, a pentose sugar ribose, and the nucleobase guanine. GDP is the product ...
Nucleotides Coenzymes {{biochem-stub