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Sphingolipids
Sphingolipids are a class of lipids containing a backbone of sphingoid bases, a set of aliphatic amino alcohols that includes sphingosine. They were discovered in brain extracts in the 1870s and were named after the mythological sphinx because of their enigmatic nature. These compounds play important roles in signal transduction and cell recognition. Sphingolipidoses, or disorders of sphingolipid metabolism, have particular impact on neural tissue. A sphingolipid with an R group consisting of a hydrogen atom only is a ceramide. Other common R groups include phosphocholine, yielding a sphingomyelin, and various sugar monomers or dimers, yielding cerebrosides and globosides, respectively. Cerebrosides and globosides are collectively known as glycosphingolipids. Structure The long-chain bases, sometimes simply known as sphingoid bases, are the first non-transient products of '' de novo'' sphingolipid synthesis in both yeast and mammals. These compounds, specifically known as phytosp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sphingolipids General Structures
Sphingolipids are a class of lipids containing a backbone of sphingoid bases, a set of aliphatic amino alcohols that includes sphingosine. They were discovered in brain extracts in the 1870s and were named after the mythological sphinx because of their enigmatic nature. These compounds play important roles in signal transduction and cell recognition. Sphingolipidoses, or disorders of sphingolipid metabolism, have particular impact on neural tissue. A sphingolipid with an R group consisting of a hydrogen atom only is a ceramide. Other common R groups include phosphocholine, yielding a sphingomyelin, and various sugar monomers or dimers, yielding cerebrosides and globosides, respectively. Cerebrosides and globosides are collectively known as glycosphingolipids. Structure The long-chain bases, sometimes simply known as sphingoid bases, are the first non-transient products of '' de novo'' sphingolipid synthesis in both yeast and mammals. These compounds, specifically known as phytos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lipid
Lipids are a broad group of naturally-occurring molecules which includes fats, waxes, sterols, fat-soluble vitamins (such as vitamins A, D, E and K), monoglycerides, diglycerides, phospholipids, and others. The functions of lipids include storing energy, signaling, and acting as structural components of cell membranes. Lipids have applications in the cosmetic and food industries, and in nanotechnology. Lipids may be broadly defined as hydrophobic or amphiphilic small molecules; the amphiphilic nature of some lipids allows them to form structures such as vesicles, multilamellar/unilamellar liposomes, or membranes in an aqueous environment. Biological lipids originate entirely or in part from two distinct types of biochemical subunits or "building-blocks": ketoacyl and isoprene groups. Using this approach, lipids may be divided into eight categories: fatty acyls, glycerolipids, glycerophospholipids, sphingolipids, saccharolipids, and polyketides (derived from condensati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sphingomyelin
Sphingomyelin (SPH, ˌsfɪŋɡoˈmaɪəlɪn) is a type of sphingolipid found in animal cell membranes, especially in the membranous myelin sheath that surrounds some nerve cell axons. It usually consists of phosphocholine and ceramide, or a ethanolamine, phosphoethanolamine head group; therefore, sphingomyelins can also be classified as sphingophospholipids. In humans, SPH represents ~85% of all sphingolipids, and typically make up 10–20 mol % of plasma membrane lipids. Sphingomyelin was first isolated by Germans, German chemist Johann Ludwig Wilhelm Thudichum, Johann L.W. Thudicum in the 1880s. The structure of sphingomyelin was first reported in 1927 as N-acyl-sphingosine-1-phosphorylcholine. Sphingomyelin content in mammals ranges from 2 to 15% in most tissues, with higher concentrations found in nerve tissues, red blood cells, and the ocular lenses. Sphingomyelin has significant structural and functional roles in the cell. It is a plasma membrane component and parti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sphingomyelin
Sphingomyelin (SPH, ˌsfɪŋɡoˈmaɪəlɪn) is a type of sphingolipid found in animal cell membranes, especially in the membranous myelin sheath that surrounds some nerve cell axons. It usually consists of phosphocholine and ceramide, or a ethanolamine, phosphoethanolamine head group; therefore, sphingomyelins can also be classified as sphingophospholipids. In humans, SPH represents ~85% of all sphingolipids, and typically make up 10–20 mol % of plasma membrane lipids. Sphingomyelin was first isolated by Germans, German chemist Johann Ludwig Wilhelm Thudichum, Johann L.W. Thudicum in the 1880s. The structure of sphingomyelin was first reported in 1927 as N-acyl-sphingosine-1-phosphorylcholine. Sphingomyelin content in mammals ranges from 2 to 15% in most tissues, with higher concentrations found in nerve tissues, red blood cells, and the ocular lenses. Sphingomyelin has significant structural and functional roles in the cell. It is a plasma membrane component and parti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ceramide
Ceramides are a family of waxy lipid molecules. A ceramide is composed of N-acetylsphingosine and a fatty acid. Ceramides are found in high concentrations within the cell membrane of eukaryotic cells, since they are component lipids that make up sphingomyelin, one of the major lipids in the lipid bilayer. Contrary to previous assumptions that ceramides and other sphingolipids found in cell membrane were purely supporting structural elements, ceramide can participate in a variety of cellular signaling: examples include regulating differentiation, proliferation, and programmed cell death (PCD) of cells. The word ''ceramide'' comes from the Latin ''cera'' (wax) and ''amide''. Ceramide is a component of vernix caseosa, the waxy or cheese-like white substance found coating the skin of newborn human infants. Pathways for ceramide synthesis There are three major pathways of ceramide generation. First, the sphingomyelinase pathway uses an enzyme to break down sphingomyelin in the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phytoceramide
Ceramides are a family of waxy lipid molecules. A ceramide is composed of N-acetylsphingosine and a fatty acid. Ceramides are found in high concentrations within the cell membrane of eukaryotic cells, since they are component lipids that make up sphingomyelin, one of the major lipids in the lipid bilayer. Contrary to previous assumptions that ceramides and other sphingolipids found in cell membrane were purely supporting structural elements, ceramide can participate in a variety of cellular signaling: examples include regulating differentiation, proliferation, and programmed cell death (PCD) of cells. The word ''ceramide'' comes from the Latin ''cera'' (wax) and ''amide''. Ceramide is a component of vernix caseosa, the waxy or cheese-like white substance found coating the skin of newborn human infants. Pathways for ceramide synthesis There are three major pathways of ceramide generation. First, the sphingomyelinase pathway uses an enzyme to break down sphingomyelin in the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ceramide
Ceramides are a family of waxy lipid molecules. A ceramide is composed of N-acetylsphingosine and a fatty acid. Ceramides are found in high concentrations within the cell membrane of eukaryotic cells, since they are component lipids that make up sphingomyelin, one of the major lipids in the lipid bilayer. Contrary to previous assumptions that ceramides and other sphingolipids found in cell membrane were purely supporting structural elements, ceramide can participate in a variety of cellular signaling: examples include regulating differentiation, proliferation, and programmed cell death (PCD) of cells. The word ''ceramide'' comes from the Latin ''cera'' (wax) and ''amide''. Ceramide is a component of vernix caseosa, the waxy or cheese-like white substance found coating the skin of newborn human infants. Pathways for ceramide synthesis There are three major pathways of ceramide generation. First, the sphingomyelinase pathway uses an enzyme to break down sphingomyelin in the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ceramides
Ceramides are a family of waxy lipid molecules. A ceramide is composed of N-acetylsphingosine and a fatty acid. Ceramides are found in high concentrations within the cell membrane of eukaryotic cells, since they are component lipids that make up sphingomyelin, one of the major lipids in the lipid bilayer. Contrary to previous assumptions that ceramides and other sphingolipids found in cell membrane were purely supporting structural elements, ceramide can participate in a variety of cellular signaling: examples include regulating differentiation, proliferation, and programmed cell death (PCD) of cells. The word ''ceramide'' comes from the Latin ''cera'' (wax) and ''amide''. Ceramide is a component of vernix caseosa, the waxy or cheese-like white substance found coating the skin of newborn human infants. Pathways for ceramide synthesis There are three major pathways of ceramide generation. First, the sphingomyelinase pathway uses an enzyme to break down sphingomyelin in the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cerebroside
Cerebrosides is the common name for a group of glycosphingolipids called monoglycosylceramides which are important components in animal muscle and nerve cell membranes. They consist of a ceramide with a single sugar residue at the 1-hydroxyl moiety. The sugar residue can be either glucose or galactose; the two major types are therefore called glucocerebrosides (a.k.a. glucosylceramides) and galactocerebrosides (a.k.a. galactosylceramides). Galactocerebrosides are typically found in neural tissue, while glucocerebrosides are found in other tissues. Structure The fundamental structure of a cerebroside is ceramide. Monoglycosyl and oligoglycosylceramides having a mono or polysaccharide bonded glycosidically to the terminal OH group of ceramide are defined as cerebrosides. Sphingosine is the main long-chain base present in ceramide. Galactosylceramide is the principal glycosphingolipid in brain tissue. Galactosylceramides are present in all nervous tissues, and can compose up to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glycosphingolipid
Glycosphingolipids are a subtype of glycolipids containing the amino alcohol sphingosine. They may be considered as sphingolipids with an attached carbohydrate. Glycosphingolipids are a group of lipids (more specifically, sphingolipids) and are a part of the cell membrane. They consist of a hydrophobic ceramide part and a glycosidically bound carbohydrate part. This oligosaccharide content remains on the outside of the cell membrane where it is important for biological processes such as cell adhesion or cell–cell interactions. Glycosphingolipids play also important role in oncogenesis and ontogenesis. Classification In general, glycosphingolipids can be categorized into two groups: neutral glycosphingolipids (also called glycosphingolipids) and negatively charged glycosphingolipids. The latter can be distinguished again by means of the charge carrier. While in gangliosides sialic acids are found, sulfatides have a sulfate group. The structural similarity of most glycolipids is t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sphingosine
Sphingosine (2-amino-4-trans-octadecene-1,3-diol) is an 18-carbon amino alcohol with an unsaturated hydrocarbon chain, which forms a primary part of sphingolipids, a class of cell membrane lipids that include sphingomyelin, an important phospholipid. Functions Sphingosine can be phosphorylated in vivo via two kinases, sphingosine kinase type 1 and sphingosine kinase type 2. This leads to the formation of sphingosine-1-phosphate, a potent signaling lipid. Sphingolipid metabolites, such as ceramides, sphingosine and sphingosine-1-phosphate, are lipid signaling molecules involved in diverse cellular processes. Biosynthesis Sphingosine is synthesized from palmitoyl CoA and serine in a condensation required to yield dihydrosphingosine. Dehydrosphingosine is then reduced by NADPH to dihydrosphingosine (sphinganine), acylated to dihydroceramide finally oxidized by FAD to ceramide. Sphingosine is then solely formed via degradation of sphingolipid in the lysosome. See also * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Globoside
Globosides are a sub-class of the lipid class glycosphingolipid with three to nine sugar molecules as the side chain (or R group) of ceramide. The sugars are usually a combination of ''N''-acetylgalactosamine, D-glucose or D-galactose. One characteristic of globosides is that the "core" sugars consists of Glucose-Galactose-Galactose (Ceramide-βGlc4-1βGal4-1αGal), like in the case of the most basic globosidGb3 also known as pk-antigen. Another important characteristic of globosides is that they are neutral at pH 7, because they usually do not contain neuraminic acid, a sugar with an acidic carboxy-group. However, some globosides with the core structure Cer-Glc-Gal-Gal do contain neuraminic acid, e.g. the globo-series glycosphingolipid "SSEA-4-antigen" The side chain can be cleaved by galactosidases and glucosidases. The deficiency of α-galactosidase A causes Fabry's disease, an inherited metabolic disease characterized by the accumulation of the globoside globotriaosylceram ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
