In nucleotide sugar metabolism a group of
biochemicals known as
nucleotide sugars act as donors for sugar residues in the
glycosylation reactions that produce
polysaccharides.
They are substrates 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 glyco ...
s. The nucleotide sugars are also intermediates in nucleotide sugar interconversions that produce some of the activated sugars needed for glycosylation reactions.
[ Since most glycosylation takes place in the endoplasmic reticulum and ]golgi apparatus
The Golgi apparatus (), also known as the Golgi complex, Golgi body, or simply the Golgi, is an organelle found in most eukaryotic cells. Part of the endomembrane system in the cytoplasm, it packages proteins into membrane-bound vesicles ...
, there are a large family of nucleotide sugar transporters that allow nucleotide sugars to move from the cytoplasm
In cell biology, the cytoplasm is all of the material within a eukaryotic cell, enclosed by the cell membrane, except for the cell nucleus. The material inside the nucleus and contained within the nuclear membrane is termed the nucleoplasm. ...
, where they are produced, into the organelles where they are consumed.
Nucleotide sugar metabolism is particularly well-studied in yeast, fungal pathogens, and bacterial pathogen
In biology, a pathogen ( el, πάθος, "suffering", "passion" and , "producer of") in the oldest and broadest sense, is any organism or agent that can produce disease. A pathogen may also be referred to as an infectious agent, or simply a germ ...
s, such as '' E. coli'' and '' Mycobacterium tuberculosis'', since these molecules are required for the synthesis of glycoconjugate
Glycoconjugates are the classification family for carbohydrates – referred to as glycans – which are covalently linked with chemical species such as proteins, peptides, lipids, and other compounds. Glycoconjugates are formed in processes ter ...
s on the surfaces of these organisms. These glycoconjugates are virulence factor
Virulence factors (preferably known as pathogenicity factors or effectors in plant science) are cellular structures, molecules and regulatory systems that enable microbial pathogens (bacteria, viruses, fungi, and protozoa) to achieve the following ...
s and components of the fungal and bacterial cell wall. These pathways are also studied in plant
Plants are predominantly photosynthetic eukaryotes of the kingdom Plantae. Historically, the plant kingdom encompassed all living things that were not animals, and included algae and fungi; however, all current definitions of Plantae exclu ...
s, but here the enzymes involved are less well understood.
References
Metabolism
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