Glycosaminoglycans (GAGs) or mucopolysaccharides are long, linear polysaccharides consisting of repeating disaccharide units. The repeating two-sugar unit consists of a uronic sugar and an amino sugar, except in the case of the sulfated glycosaminoglycan keratan, where, in place of the uronic sugar there is a galactose unit. GAGs are found in vertebrates, invertebrates and bacteria. Because GAGs are highly polar molecules and attract water; the body uses them as lubricants or shock absorbers.
Heparan sulfate (HS) is a linear polysaccharide found in all animal tissues. It occurs as a proteoglycan in which two or three HS chains are attached in close proximity to cell surface or extracellular matrix proteins. In this form, HS binds to a variety of protein ligands, including Wnt, and regulates a wide range of biological activities, including developmental processes, angiogenesis, blood coagulation, abolishing detachment activity by GrB, and tumour metastasis. HS has also been shown to serve as cellular receptor for a number of viruses, including the respiratory syncytial virus. One study suggests that cellular heparan sulfate has a role in SARS-CoV-2 Infection, particularly when the virus attaches with ACE2.
N-acetylgalactosamine-4-sulfatase is an enzyme with systematic name N-acetyl-D-galactosamine-4-sulfate 4-sulfohydrolase. It catalyses the following reaction:
The enzyme N-acetylgalactosamine-6-sulfatase catalyzes the chemical reaction of cleaving off the 6-sulfate groups of the N-acetyl-D-galactosamine 6-sulfate units of the macromolecule chondroitin sulfate and, similarly, of the D-galactose 6-sulfate units of the macromolecule keratan sulfate.
In enzymology, a N-acetylgalactosaminyl-proteoglycan 3-beta-glucuronosyltransferase is an enzyme that catalyzes the chemical reaction
Carbohydrate sulfotransferase 15 is an enzyme that in humans is encoded by the CHST15 gene. It belongs to the N-acetylgalactosamine 4-sulfate 6-O-sulfotransferase enzyme class.
Carbohydrate sulfotransferase 11 is an enzyme that in humans is encoded by the CHST11 gene.
Carbohydrate sulfotransferase 12 is an enzyme that in humans is encoded by the CHST12 gene.
Chondroitin sulfate N-acetylgalactosaminyltransferase 1 is an enzyme that in humans is encoded by the CSGALNACT1 gene.
Carbohydrate sulfotransferase 7 is an enzyme that in humans is encoded by the CHST7 gene.
Carbohydrate sulfotransferase 14 is an enzyme that in humans is encoded by the CHST14 gene.
Carbohydrate sulfotransferases are sulfotransferase enzymes that transfer sulfate to carbohydrate groups in glycoproteins and glycolipids. Carbohydrates are used by cells for a wide range of functions from structural purposes to extracellular communication. Carbohydrates are suitable for such a wide variety of functions due to the diversity in structure generated from monosaccharide composition, glycosidic linkage positions, chain branching, and covalent modification. Possible covalent modifications include acetylation, methylation, phosphorylation, and sulfation. Sulfation, performed by carbohydrate sulfotransferases, generates carbohydrate sulfate esters. These sulfate esters are only located extracellularly, whether through excretion into the extracellular matrix (ECM) or by presentation on the cell surface. As extracellular compounds, sulfated carbohydrates are mediators of intercellular communication, cellular adhesion, and ECM maintenance.
Glucuronylgalactosylproteoglycan 4-beta-N-acetylgalactosaminyltransferase is an enzyme with systematic name UDP-N-acetyl-D-galactosamine:D-glucuronyl-(1->3)-beta-D-galactosyl-proteoglycan 4-beta-N-acetylgalactosaminyltransferase. This enzyme catalyses the following chemical reaction
Glucuronosyl-N-acetylgalactosaminyl-proteoglycan 4-beta-N-acetylgalactosaminyltransferase is an enzyme with systematic name UDP-N-acetyl-D-galactosamine:beta-D-glucuronosyl-(1->3)-N-acetyl-beta-D-galactosaminyl-proteoglycan 4-beta-N-acetylgalactosaminyltransferase. This enzyme catalyses the following chemical reaction
Glucuronyl-galactosyl-proteoglycan 4-alpha-N-acetylglucosaminyltransferase is an enzyme with systematic name UDP-N-acetyl-D-glucosamine:beta-D-glucuronosyl-(1->3)-beta-D-galactosyl-(1->3)-beta-D-galactosyl-(1->4)-beta-D-xylosyl-proteoglycan 4IV-alpha-N-acetyl-D-glucosaminyltransferase. This enzyme catalyses the following chemical reaction
Glucuronosyl-N-acetylglucosaminyl-proteoglycan 4-alpha-N-acetylglucosaminyltransferase is an enzyme with systematic name UDP-N-acetyl-D-glucosamine:beta-D-glucuronosyl-(1->4)-N-acetyl-alpha-D-glucosaminyl-proteoglycan 4-alpha-N-acetylglucosaminyltransferase. This enzyme catalyses the following chemical reaction
UDP-N-acetylgalactosamine diphosphorylase is an enzyme with systematic name UTP:N-acetyl-alpha-D-galactosamine-1-phosphate uridylyltransferase. This enzyme catalyses the following chemical reaction
N-acetylgalactosamine 4-sulfate 6-O-sulfotransferase is an enzyme with systematic name 3'-phosphoadenylyl-sulfate:(dermatan)-4-O-sulfo-N-acetyl-D-galactosamine 6-O-sulfotransferase. This enzyme catalyses the following chemical reaction
Unsaturated chondroitin disaccharide hydrolase (EC 3.2.1.180, UGL, unsaturated glucuronyl hydrolase) is an enzyme with systematic name beta-D-4-deoxy-Delta4-GlcAp-(1->3)-beta-D-GalNAc6S hydrolase. This enzyme catalyses the following chemical reaction
Carbohydrate sulfotransferase 13 is a protein that is encoded in humans by the CHST13 gene.
