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Sphingolipid Activator Protein
Prosaposin, also known as PSAP, is a protein which in humans is encoded by the ''PSAP'' gene. This highly conserved glycoprotein is a precursor for 4 cleavage products: saposins A, B, C, and D. Saposin is an acronym for Sphingolipid Activator PrO ''SeINs. Each domain of the precursor protein is approximately 80 amino acid residues long with nearly identical placement of cysteine residues and glycosylation sites. Saposins A-D localize primarily to the lysosomal compartment where they facilitate the catabolism of glycosphingolipids with short oligosaccharide groups. The precursor protein exists both as a secretory protein and as an integral membrane protein and has neurotrophic activities. Saposins A–D are required for the hydrolysis of certain sphingolipids by specific lysosomal hydrolases. Family members * Saposin A was identified as an N-terminal domain in the prosaposin cDNA prior to its isolation. It is known to stimulate the enzymatic hydrolysis of 4-methylumbelliferyl-β ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residue (biochemistry), residues. Proteins perform a vast array of functions within organisms, including Enzyme catalysis, catalysing metabolic reactions, DNA replication, Cell signaling, responding to stimuli, providing Cytoskeleton, structure to cells and Fibrous protein, organisms, and Intracellular transport, transporting molecules from one location to another. Proteins differ from one another primarily in their sequence of amino acids, which is dictated by the Nucleic acid sequence, nucleotide sequence of their genes, and which usually results in protein folding into a specific Protein structure, 3D structure that determines its activity. A linear chain of amino acid residues is called a polypeptide. A protein contains at least one long polypeptide. Short polypeptides, containing less than 20–30 residues, are rarely considered to be proteins and are commonly called pep ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arylsulfatase A
Arylsulfatase A (or cerebroside-sulfatase) is an enzyme that breaks down sulfatides, namely cerebroside 3-sulfate into cerebroside and sulfate. In humans, arylsulfatase A is encoded by the ''ARSA'' gene. Clinical significance A deficiency in Arylsulfatase A is associated with metachromatic leukodystrophy, an autosomal recessive In genetics, dominance is the phenomenon of one variant (allele) of a gene on a chromosome masking or overriding the effect of a different variant of the same gene on the other copy of the chromosome. The first variant is termed dominant and ... disease. Multiple sulfatase deficiency (MSD) is also associated with the ARSA gene. Biochemistry Enzyme regulation Arylsulfatase A is inhibited by phosphate, which forms a covalent bond with the active site 3-oxoalanine. ; References Further reading * * * * * * * * * * * * * * * * * * External links GeneReviews/NCBI/NIH/UW entry on Arylsulfatase A Deficiency - Metachromatic Leukodystrophy OMIM ent ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Combined Saposin Deficiency
Combined Saposin Defiency is a very rare Metabolic disorder, metabolic and genetic disorder that is caused by the mutation in a gene Prosaposin, PSAP. This disease belongs to Lysosomal storage disease, Lysosomal Storage Diseases(LSDs). Because of complete saposin deficiency, it can cause clinical features of 4 diseases(Gaucher's disease, Gaucher’s Disease, Metachromatic leukodystrophy, Metachromatic Leukodystrophy, Farber disease, Farber’s Disease, Krabbe disease, Krabbe’s Disease) to be apparent. Cause PSAPD is caused by mutations in a Prosaposin, PSAP gene, which is located on the long arm of chromosome 10 (10q22.1). PSAPD is inherited in a Autosomal Recessive fashion. Symptoms Symptoms usually start in infancy or in neonatal age. The signs of this disease are respiratory failure, hepatosplenomegaly, Dysphagia, poor feeding, myoclonus, Hyperkinesia, hyperkinetic movements, Clonus, clonic seizures, leukodystrophy, hypotonia, Eye disease, abnormality of eye movement and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metachromatic Leukodystrophy
Metachromatic leukodystrophy (MLD) is a lysosomal storage disease which is commonly listed in the family of leukodystrophies as well as among the sphingolipidoses as it affects the metabolism of sphingolipids. Leukodystrophies affect the growth and/or development of myelin, the fatty covering that acts as an insulator around nerve fibers throughout the central and peripheral nervous systems. MLD involves cerebroside sulfate accumulation. Metachromatic leukodystrophy, like most enzyme deficiencies, has an autosomal recessive inheritance pattern. Signs and symptoms Like many other genetic disorders that affect lipid metabolism, there are several forms of MLD, which are late infantile, juvenile, and adult. * In the ''late infantile form'', which is the most common form of MLD (50–60%), affected children begin having difficulty walking after the first year of life, usually at 15–24 months. Symptoms include muscle wasting and weakness, muscle rigidity, developmental delay ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tay–Sachs Disease
Tay–Sachs disease is an Genetic disorder, inherited fatal lysosomal storage disease that results in the destruction of nerve cells in the brain and spinal cord. The most common form is infantile Tay–Sachs disease, which becomes apparent around the age of three to six months of age, with the infant losing the ability to turn over, sit, or crawl. This is then followed by seizures, hearing loss, and paralysis, inability to move, with death usually occurring by the age of three to five. Less commonly, the disease may occur later in childhood, adolescence, or adulthood (juvenile or late-onset). These forms tend to be less severe, but the juvenile form typically results in death by the age of 15. Tay–Sachs disease is caused by a genetic mutation in the ''HEXA'' gene on chromosome 15, which codes a Protein subunit, subunit of the hexosaminidase enzyme known as hexosaminidase A. It is inherited in an autosomal recessive manner. The mutation disrupts the activity of the enzyme, whi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gaucher Disease
Gaucher's disease or Gaucher disease () (GD) is a genetic disorder in which glucocerebroside (a sphingolipid, also known as glucosylceramide) accumulates in cells and certain organs. The disorder is characterized by bruising, fatigue, anemia, low blood platelet count and enlargement of the liver and spleen, and is caused by a hereditary deficiency of the enzyme glucocerebrosidase (also known as glucosylceramidase), which acts on glucocerebroside. When the enzyme is defective, glucocerebroside accumulates, particularly in white blood cells and especially in macrophages (mononuclear leukocytes, which is often a target for intracellular parasites). Glucocerebroside can collect in the spleen, liver, kidneys, lungs, brain, and bone marrow. Manifestations may include enlarged spleen and liver, liver malfunction, skeletal disorders or bone lesions that may be painful, severe neurological complications, swelling of lymph nodes and (occasionally) adjacent joints, distended abdomen, a brownis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Degradative Enzyme
A degradative enzyme is an enzyme (in a broader sense a protein) which degrades biological molecules. Some examples of degradative enzymes: *Lipase, which digests lipids, * Carbohydrases, which digest carbohydrates (e.g., sugars), *Proteases, which digest proteins,Hedstrom L. ''Serine Protease Mechanism and Specificity.'' Chem Rev 2002;102:4501-4523. *Nucleases, which digest nucleic acids. *Cathelicidins, antimicrobial polypeptides found in lysosomes. References See also * Hydrolase In biochemistry, hydrolases constitute a class of enzymes that commonly function as biochemical catalysts that use water to break a chemical bond: :\ce \quad \xrightarrowtext\quad \ce This typically results in dividing a larger molecule into s ... Enzymes {{Enzyme-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
GM2A
GM2 ganglioside activator also known as GM2A is a protein which in humans is encoded by the ''GM2A'' gene. Function The protein encoded by this gene is a small glycolipid transport protein which acts as a substrate specific co-factor for the lysosomal enzyme β-hexosaminidase A. β-hexosaminidase A, together with GM2 ganglioside activator, catalyzes the degradation of the ganglioside GM2, and other molecules containing terminal N-acetyl hexosamines. GM2A is a lipid transfer protein that stimulates the enzymatic processing of gangliosides, and also T-cell activation through lipid presentation. This protein binds molecules of ganglioside GM2, extracts them from membranes, and presents them to beta-hexosaminidase A for cleavage of N-acetyl-D-galactosamine and conversion to GM3. It was identified as a member of ML domain family of proteins involved in innate immunity and lipid metabolism in the SMART database. Regulation In melanocytic cells GM2A gene expression may be reg ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sulfatide
Sulfatide, also known as 3-O-sulfogalactosylceramide, SM4, or sulfated galactocerebroside, is a class of sulfolipids, specifically a class of sulfoglycolipids, which are glycolipids that contain a sulfate group. Sulfatide is synthesized primarily starting in the endoplasmic reticulum and ending in the Golgi apparatus where ceramide is converted to galactocerebroside and later sulfated to make sulfatide. Of all of the galactolipids that are found in the myelin sheath, one fifth of them are sulfatide. Sulfatide is primarily found on the extracellular leaflet of the myelin plasma membrane produced by the oligodendrocytes in the central nervous system and in the Schwann cells in the peripheral nervous system. However, sulfatide is also present on the extracellular leaflet of the plasma membrane of many cells in eukaryote, eukaryotic organisms. Since sulfatide is a multifunctional molecule, it can be used in multiple biological areas. Aside from being a membrane component, sulfatide func ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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: protein-coding genes and non-coding genes. During gene expression (the synthesis of Gene product, RNA or protein from a gene), DNA is first transcription (biology), copied into RNA. RNA can be non-coding RNA, directly functional or be the intermediate protein biosynthesis, template for the synthesis of a protein. The transmission of genes to an organism's offspring, is the basis of the inheritance of phenotypic traits from one generation to the next. These genes make up different DNA sequences, together called a genotype, that is specific to every given individual, within the gene pool of the population (biology), population of a given species. The genotype, along with environmental and developmental factors, ultimately determines the phenotype ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Galactocerebroside
A galactosylceramide, or galactocerebroside is a type of cerebroside consisting of a ceramide with a galactose residue at the 1-hydroxyl moiety. The galactose is cleaved by galactosylceramidase. Galactosylceramide is a marker for oligodendrocytes in the brain, whether or not they form myelin. Additional images File:Sphingolipid.png, Sphingolipid See also * Alpha-Galactosylceramide * Krabbe disease * Myelin Myelin Sheath ( ) is a lipid-rich material that in most vertebrates surrounds the axons of neurons to insulate them and increase the rate at which electrical impulses (called action potentials) pass along the axon. The myelinated axon can be lik ... References External links *CHEMBL110111 Glycolipids {{biochemistry-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glucocerebroside
Glucocerebroside (also called glucosylceramide) is any of the cerebrosides in which the monosaccharide head group is glucose. Research conducted on glucocerebrosides has shown that glucocerebrosides help support cellular functions in humans, such as signaling pathways as well as being possibly linked to diseases. Certain symptoms of diseases such as Gaucher's and Parkinson's disease have been linked to abnormal changes in glucocerebroside metabolism, such as changes in glucocerebroside levels and regulation. Researchers have also started to study the role of glucocerebrosides in cancer. In Gaucher's disease, the enzyme glucocerebrosidase is nonfunctional and cannot break down glucocerebroside into glucose and ceramide in the lysosome. Affected macrophages, called Gaucher cells, have a distinct appearance similar to "wrinkled tissue paper" under light microscopy, because the substrates build-up within the lysosome. In 2019, research conducted by Lee et al., shows that gluco ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
