Mucopolysaccharidoses are a group of metabolic disorders caused by the absence or malfunctioning of lysosomal enzymes needed to break down molecules called glycosaminoglycans (GAGs). These long chains of sugar carbohydrates occur within the cells that help build bone, cartilage, tendons, corneas, skin and connective tissue. GAGs are also found in the fluids that lubricate joints.
Sanfilippo syndrome, also known as mucopolysaccharidosis type III (MPS III), is a rare autosomal recessive lysosomal storage disease that primarily affects the brain and spinal cord. It is caused by a buildup of large sugar molecules called glycosaminoglycans (AKA GAGs, or mucopolysaccharides) in the body's lysosomes.
The terms glycans and polysaccharides are defined by IUPAC as synonyms meaning "compounds consisting of a large number of monosaccharides linked glycosidically". However, in practice the term glycan may also be used to refer to the carbohydrate portion of a glycoconjugate, such as a glycoprotein, glycolipid, or a proteoglycan, even if the carbohydrate is only an oligosaccharide. Glycans usually consist solely of O-glycosidic linkages of monosaccharides. For example, cellulose is a glycan composed of β-1,4-linked D-glucose, and chitin is a glycan composed of β-1,4-linked N-acetyl-D-glucosamine. Glycans can be homo- or heteropolymers of monosaccharide residues, and can be linear or branched.
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.
Hunter syndrome, or mucopolysaccharidosis type II, is a rare genetic disorder in which large sugar molecules called glycosaminoglycans build up in body tissues. It is a form of lysosomal storage disease. Hunter syndrome is caused by a deficiency of the lysosomal enzyme iduronate-2-sulfatase (I2S). The lack of this enzyme causes heparan sulfate and dermatan sulfate to accumulate in all body tissues. Hunter syndrome is the only MPS syndrome to exhibit X-linked recessive inheritance.
Sulfatases EC 3.1.6.- are enzymes of the esterase class that catalyze the hydrolysis of sulfate esters. These may be found on a range of substrates, including steroids, carbohydrates and proteins. Sulfate esters may be formed from various alcohols and amines. In the latter case the resultant N-sulfates can also be termed sulfamates.
Arylsulfatase B is an enzyme associated with mucopolysaccharidosis VI.
Iduronate 2-sulfatase is a sulfatase enzyme associated with Hunter syndrome. It catalyses hydrolysis of the 2-sulfate groups of the L-iduronate 2-sulfate units of dermatan sulfate, heparan sulfate and heparin.
N-acetylgalactosamine-4-sulfatase is an enzyme with systematic name N-acetyl-D-galactosamine-4-sulfate 4-sulfohydrolase. It catalyses the following reaction:
N-acetylgalactosamine-6-sulfatase is an enzyme that, in humans, is encoded by the GALNS gene.
The enzyme α-N-acetylglucosaminidase is a protein associated with Sanfilippo syndrome, with systematic name α-N-acetyl-D-glucosaminide N-acetylglucosaminohydrolase. It catalyses the hydrolysis of terminal non-reducing N-acetyl-D-glucosamine residues in N-acetyl-α-D-glucosaminides, and also UDP-N-acetylglucosamine.
In enzymology, an UDP-N-acetylglucosamine 4-epimerase is an enzyme that catalyzes the chemical reaction
In enzymology, a N-sulfoglucosamine sulfohydrolase (EC 3.10.1.1), otherwise known as SGSH, is an enzyme that catalyzes the chemical 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.
The enzyme N-sulfoglucosamine-3-sulfatase catalyzes cleaving off the 3-sulfate groups of the N-sulfo-D-glucosamine 3-O-sulfate units of heparin.
N-sulphoglucosamine sulphohydrolase is an enzyme that in humans is encoded by the SGSH gene.
Sulfatase 1, also known as SULF1, is an enzyme which in humans is encoded by the SULF1 gene.
Heparan-α-glucosaminide N-acetyltransferase is an enzyme that in humans is encoded by the HGSNAT gene.
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
N-acetylglucosaminidase, alpha is a protein that in humans is encoded by the NAGLU gene.
