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Glycoaminoglycans
Glycosaminoglycans (GAGs) or mucopolysaccharides are long, linear polysaccharides consisting of repeating disaccharide units (i.e. two-sugar 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. Mucopolysaccharidoses are a group of metabolic disorders in which abnormal accumulations of glycosaminoglycans occur due to enzyme deficiencies. Production Glycosaminoglycans vary greatly in molecular mass, disaccharide structure, and sulfation. This is because GAG synthesis is not template driven, as are proteins or nucleic acids, but constantly altered by processing enzymes. GAGs are classified into four groups, based on their core disaccharide structures: # Hepar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chondroitin Sulfate Structure NTP
A chondroitin is a chondrin derivative. Types include: * Chondroitin sulfate * Dermatan sulfate Chondroitin as a supplement is now commonly used (often in combination with glucosamine) in treating the joint disease of osteoarthritis. In contrast to the symptomatic treatments, chondroitin can modify the progression of a disease process in the patient which it can be used as an alternative medicine. Chondroitin's effect toward the articular cartilage integrity as it is part of the proteoglycan Proteoglycans are proteins that are heavily glycosylated. The basic proteoglycan unit consists of a "core protein" with one or more covalently attached glycosaminoglycan (GAG) chain(s). The point of attachment is a serine (Ser) residue to w ... molecules. The cartilage proteoglycan synthesis can speed up as chondroitin is going through the pathway of the alimentary canal. Research has been conducted to show the effectiveness of chondroitin and results indicate that it helps to manage ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rough Endoplasmic Reticulum
The endoplasmic reticulum (ER) is a part of a transportation system of the eukaryotic cell, and has many other important functions such as protein folding. The word endoplasmic means "within the cytoplasm", and reticulum is Latin for "little net". It is a type of organelle made up of two subunits – rough endoplasmic reticulum (RER), and smooth endoplasmic reticulum (SER). The endoplasmic reticulum is found in most eukaryotic cells and forms an interconnected network of flattened, membrane-enclosed sacs known as cisternae (in the RER), and tubular structures in the SER. The membranes of the ER are continuous with the outer nuclear membrane. The endoplasmic reticulum is not found in red blood cells, or spermatozoa. There are two types of ER that share many of the same proteins and engage in certain common activities such as the synthesis of certain lipids and cholesterol. Different types of cells contain different ratios of the two types of ER depending on the activities of t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Keratocan
Keratocan (KTN) also known as keratan sulfate proteoglycan keratocan, is a protein that in humans is encoded by the ''KERA'' gene. Keratan sulfate proteoglycans (KSPGs) are members of the small leucine-rich proteoglycan (SLRP) family. KSPGs, particularly keratocan, lumican and mimecan, are important to the transparency of the cornea The cornea is the transparency (optics), transparent front part of the eyeball which covers the Iris (anatomy), iris, pupil, and Anterior chamber of eyeball, anterior chamber. Along with the anterior chamber and Lens (anatomy), lens, the cornea .... Mutations of the gene cause cornea plana 2. References Further reading * * * * * * * * * * * * * * * * {{gene-12-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lumican
Lumican, also known as LUM, is an extracellular matrix protein that, in humans, is encoded by the ''LUM'' gene on chromosome 12. Structure Lumican is a proteoglycan Class II member of the small leucine-rich proteoglycan (SLRP) family that includes decorin, biglycan, fibromodulin, keratocan, epiphycan, and osteoglycin. Like the other SLRPs, lumican has a molecular weight of about 40 kilodaltons and has four major intramolecular domains: #a signal peptide of 16 amino acid residues; #a negatively-charged N-terminal domain containing sulfated tyrosine and disulfide bond(s); #ten tandem leucine-rich repeats allowing lumican to bind to other extracellular components such as collagen; #a carboxyl terminal domain of 50 amino acid residues containing two conserved cysteines 32 residues apart. There are four N-linked sites within the leucine-rich repeat domain of the protein core that can be substituted with keratan sulfate. The core protein of lumican (like decorin and fibromod ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aggrecan
Aggrecan (ACAN), also known as cartilage-specific proteoglycan core protein (CSPCP) or chondroitin sulfate proteoglycan 1, is a protein that in humans is encoded by the ''ACAN'' gene. This gene is a member of the lectican ( chondroitin sulfate proteoglycan) family. The encoded protein is an integral part of the extracellular matrix in cartilagenous tissue and it withstands compression in cartilage. Aggrecan is a proteoglycan, or a protein modified with large carbohydrates; the human form of the protein is 2316 amino acids long and can be expressed in multiple isoforms due to alternative splicing. Aggrecan was named for its ability to form large aggregates in the cartilage tissue (a large aggregating proteoglycan). Structure Aggrecan is a high molecular weight ( molar mass between 1 million and 3 million) proteoglycan. It exhibits a bottlebrush structure, in which chondroitin sulfate and keratan sulfate glycosaminoglycan (GAG) chains are attached to an extended protein ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heparan Sulfate 6-O-sulfotransferase
Heparan sulfate 6-sulfotransferases catalyses the transfer of sulfate from adenosine 3'-phosphate, 5'-phosphosulfate to the 6th position of the N- sulfoglucosamine residue in heparan sulfate Heparan sulfate (HS) is a linear polysaccharide found in all animal tissues. It occurs in a proteoglycan (HSPG, i.e. Heparan Sulfate ProteoGlycan) in which two or three HS chains are attached in close proximity to cell surface or extracellular ma .... Human proteins containing this domain * HS6ST1 * HS6ST2 * HS6ST3 References {{DEFAULTSORT:Heparan Sulfate 6-O-Sulfotransferase EC 2.8.2 Protein domains Protein families ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heparan Sulfate 2-O-sulfotransferase
Heparan sulfate 2-O-sulfotransferase is a sulfotransferase enzyme. Heparan sulfate (HS) is a long unbranched polysaccharide found covalently attached to various proteins at the cell surface and in the extracellular matrix, where it acts as a co-receptor for a number of growth factors, morphogens, and adhesion protein Cell adhesion molecules (CAMs) are a subset of cell surface proteins that are involved in the binding of cells with other cells or with the extracellular matrix (ECM), in a process called cell adhesion. In essence, CAMs help cells stick to each ...s. HS-O-sulfotransferase (Hs2st) occupies a critical position in the succession of enzymes responsible for the biosynthesis of HS, catalysing the transfer of sulfate to the C2-position of selected hexuronic acid residues within the nascent HS chain. Mice that lack HS2ST undergo developmental failure after midgestation, the most dramatic effect being the complete failure of kidney development. This family is related to . ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NDST1
Bifunctional heparan sulfate N-deacetylase/N-sulfotransferase 1 is an enzyme. In humans, it is encoded by the ''NDST1'' gene In biology, the word gene has two meanings. The Mendelian gene is a basic unit of heredity. The molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA. There are two types of molecular genes: protei .... References Further reading * * * * * * * * * * Human proteins {{gene-5-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Xylosyltransferase
Xylosyltransferase are transferase enzymes which act upon xylose Xylose ( , , "wood") is a sugar first isolated from wood, and named for it. Xylose is classified as a monosaccharide of the aldopentose type, which means that it contains five carbon atoms and includes an aldehyde functional group. It is deriv ... and are classified under EC 2.4.2. More specifically, they can refer to: * Dolichyl-phosphate D-xylosyltransferase * Dolichyl-xylosyl-phosphate-protein xylosyltransferase * Flavonol-3-O-glycoside xylosyltransferase * Glycoprotein 2-beta-D-xylosyltransferase * Protein xylosyltransferase * Xyloglucan 6-xylosyltransferase * XYLT1 * XYLT2 * Zeatin O-beta-D-xylosyltransferase References xylosyl transferase is the first enzyme involved in the biosynthesis of glycosaminoglycan chains, an important constituent of proteoglycans. There are two types of xylosyl transferases type I and type II. EC 2.4.2 {{2.4-enzyme-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hyaluronic Acid
Hyaluronic acid (; abbreviated HA; conjugate base hyaluronate), also called hyaluronan, is an anionic, nonsulfated glycosaminoglycan distributed widely throughout connective, epithelial, and neural tissues. It is unique among glycosaminoglycans as it is non-sulfated, forms in the plasma membrane instead of the Golgi apparatus, and can be very large: human synovial HA averages about per molecule, or about 20,000 disaccharide monomers, while other sources mention . Medically, hyaluronic acid is used to treat osteoarthritis of the knee and dry eye, for wound repair, and as a cosmetic filler. The average 70 kg (150 lb) person has roughly 15 grams of hyaluronan in the body, one third of which is turned over (i.e., degraded and synthesized) per day. As one of the chief components of the extracellular matrix, it contributes significantly to cell proliferation and migration, and is involved in the progression of many malignant tumors. Hyaluronic acid is also a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
N-linked Glycosylation
''N''-linked glycosylation is the attachment of an oligosaccharide, a carbohydrate consisting of several sugar molecules, sometimes also referred to as glycan, to a nitrogen atom (the amide nitrogen of an asparagine (Asn) residue of a protein), in a process called ''N''-glycosylation, studied in biochemistry. The resulting protein is called an N-linked glycan, or simply an N-glycan. This type of linkage is important for both the structure and function of many eukaryotic proteins. The ''N''-linked glycosylation process occurs in eukaryotes and widely in archaea, but very rarely in bacteria. The nature of ''N''-linked glycans attached to a glycoprotein is determined by the protein and the cell in which it is expressed. It also varies across species. Different species synthesize different types of ''N''-linked glycans. Energetics of bond formation There are two types of bonds involved in a glycoprotein: bonds between the saccharides residues in the glycan and the linkage between ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Keratan Sulfate
Keratan sulfate (KS), also called keratosulfate, is any of several sulfated glycosaminoglycans (structural carbohydrates) that have been found especially in the cornea, cartilage, and bone. It is also synthesized in the central nervous system where it participates both in development and in the glial scar formation following an injury. Keratan sulfates are large, highly hydrated molecules which in joints can act as a cushion to absorb mechanical shock. Structure Like other glycosaminoglycans keratan sulfate is a linear polymer that consists of a repeating disaccharide unit. Keratan sulfate occurs as a proteoglycan (PG) in which KS chains are attached to cell-surface or extracellular matrix proteins, termed core proteins. KS core proteins include lumican, keratocan, mimecan, fibromodulin, PRELP, osteoadherin, and aggrecan. The basic repeating disaccharide unit within keratan sulfate is -3 Galβ1-4 GlcNAc6Sβ1-. This can be sulfated at carbon position 6 (C6) of either or bot ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
