What is sphingomyelin composed of?
Sphingomyelin is found predominantly in the plasmalemma and is composed of a long chain sphingoid base backbone (predominantly sphingosine), a fatty acid, and a phosphocholine head group.
How do you name sphingomyelin?
Naming of Sphingolipids The official names of sphingosine are (2S,3R,4E)-2-aminooctadec-4-ene-1,3-diol or D-erythro-sphingosine & E-sphing-4-enine. The abbreviation is d18:1. The first number represents the number of carbon atoms. The second number is the number of double bonds.
How is sphingomyelin structurally different from phosphatidylcholine?
Sphingomyelin is often classified and reported as a phospholipid but it is also a sphingolipid. Like phosphatidylcholine (lecithin), it contains a choline moiety and a phosphodiester linkage, but in contrast to phosphatidylcholine which is a glycerolipid, the backbone (lipid moiety) of sphingomyelin is a ceramide.
What is sphingomyelin biochemistry?
Sphingomyelin (SM) is a dominant sphingolipid in membranes of mammalian cells and this lipid class is specifically enriched in the plasma membrane, the endocytic recycling compartment, and the trans Golgi network.
How is sphingomyelin produced?
Sphingomyelin is synthesized by the transfer of phosphorylcholine from phosphatidylcholine to ceramide, liberating diacylglycerol. This reaction links glycerolipid and sphin-golipid signalling pathways, although it is not known if cells capitalize on this relationship for signalling purposes.
What is the biological function of sphingomyelin?
Sphingomyelin, localised in the plasma membrane, is a dominant sphingolipid in the membranes of mammalian cells, and plays a major role in creating lateral structures in membranes for Toll-like receptors and class A and B scavenger receptors, as well as insulin receptors [157] .
What type of lipid is sphingomyelin?
sphingolipid
Sphingomyelin (SM) is a dominant sphingolipid in membranes of mammalian cells and this lipid class is specifically enriched in the plasma membrane, the endocytic recycling compartment, and the trans Golgi network. The distribution of SM and cholesterol among cellular compartments correlate.
What is the function of sphingomyelin?
Sphingomyelin constitutes membrane microdomains such as lipid raft, caveolae, and clathrin-coated pits and implicates in the regulation of trans-membrane signaling. On the other hand, sphingomyelin emerges as an important molecule to generate bioactive sphingolipids through ceramide.
Is sphingomyelin a sphingolipid?
Sphingomyelin is an abundant sphingolipid in cellular membranes: its hydrolysis releases ceramide and phosphocholine and several stimuli are known to activate sphingomyelin hydrolysis.
What are the hydrolysis products of sphingomyelin?
What is the alcohol is sphingomyelin?
Sphingomyelins are ceramide phosphatides where the primary alcohol group forms a phosphatide (primary alcohol is esterified with a phosphoric unit that is itself esterified with choline at the second site).
What kind of structure does c24-1 sphingomyelin have?
SM (D18:1/24:1 (15Z)), also known as C24:1 sphingomyelin, belongs to the class of organic compounds known as phosphosphingolipids. These are sphingolipids with a structure based on a sphingoid base that is attached to a phosphate head group. They differ from phosphonospingolipids which have a phosphonate head group.
What makes up the phosphocholine group of sphingomyelin?
Sphingomyelin consists of a group of phosphocholine, a sphingosine and a fatty acid. It is one of the few membrane phospholipids not synthesized from glycerol. Sphingosine and fatty acid can be collectively classified as a ceramide.
Where does sphingomyelin come from in the body?
Sphingomyelin obtained from natural sources, such as bovine eggs or brain, contains fatty acids of varying chain length. Sphingomyelin with established chain length, such as palmitoylphingomyelin with a chain of 16 saturated acyl, is commercially available.
Where does conversion of sphingomyelin to ceramides occur?
For example, in animals in the sphingomyelinase pathway, conversion of sphingomyelin into ceramides (and vice versa) occurs in the plasma membrane, Golgi and mitochondria.