Both reactions require the presence of the 1-OH group of ceramide.
Details of this pathway including the identity of the presumed ceramidebinding proteins are not entirely clear.
KW - Fluorescent NBD-sphingolipids
Undesired reaction of DAST with sphingosine derivatives
Various synthetic routes to ceramide, or its preparative precursor,sphingosine, have been reported .
The intracellular site of sphingomyelin (SM) synthesis was examined in subcellular fractions from rat liver using a radioactive ceramide analog N-([1-14C]hexanoyl)-D-erythro-sphingosine. This lipid readily transferred from a complex with bovine serum albumin to liver fractions without disrupting the membranes, and was metabolized to radioactive SM. To prevent degradation of the newly synthesized SM to ceramide, all experiments were performed in the presence of EDTA to minimize neutral sphingomyelinase activity and at neutral pH to minimize acid sphingomyelinase activity. An intact Golgi apparatus fraction gave an 85-98-fold enrichment of SM synthesis and a 58-83-fold enrichment of galactosyltransferase activity. Controlled trypsin digestion demonstrated that SM synthesis was localized to the lumen of intact Golgi apparatus vesicles. Although small amounts of SM synthesis were detected in plasma membrane and rough microsome fractions, after accounting for contamination by Golgi apparatus membranes, their combined activity contributed less than 13% of the total SM synthesis in rat liver. Subfractions of the Golgi apparatus were obtained and characterized by immunoblotting and biochemical assays using cis/medial (mannosidase II) and trans (sialyltransferase and galactosyltransferase) Golgi apparatus markers. The specific activity of SM synthesis was highest in enriched cis and medial fractions but far lower in a trans fraction. We conclude that SM synthesis in rat liver occurs predominantly in the cis and medial cisternae of the Golgi apparatus and not at the plasma membrane or endoplasmic reticulum as has been previously suggested.
Sphingomyelin synthase - Wikipedia
The mammalian Golgi apparatus is composed of multiple stacks of cisternal membranes organized laterally into a ribbon-like structure, with close apposition of trans Golgi regions with specialized endoplasmic reticulum (ER) membranes. These contacts may be the site of ceramide transfer from its site of synthesis (ER) to sphingomyelin (SM) synthase through ceramide transfer protein (CERT). CERT extracts ceramide from the ER and transfers it to Golgi membranes but the role of overall Golgi structure in this process is unknown. We show here that localization of CERT in puncta around the Golgi complex requires both ER- and Golgi-binding domains of CERT. To examine how Golgi structure contributes to SM synthesis, we treated cells with Golgi-perturbing drugs and measured newly synthesized SM. Interestingly, disruption of Golgi morphology with nocodazole, but not ilimaquinone inhibited SM synthesis. Decreased localization of CERT with a Golgi marker correlated with decreased SM synthesis. We propose that some Golgi structural perturbations interfere with efficient ceramide trafficking through CERT, and thus SM synthesis. The organization of the mammalian Golgi ribbon together with CERT may promote specific ER-Golgi interactions for efficient delivery of ceramide for SM synthesis.
This should also prevent formation of sphingosine-1-phosphate whichis an additional signalling substance metabolically derived from ceramide.
In enzymology, a sphingomyelin synthase ..
proposed the term "sphingolipide" as a convenientdesignation for lipids containing sphingosine (cerebrosides, sphingomyelin,gangliosides...) ().
Carter HE et al.
discovered cyclopropane (lactobacillic acid) fatty acids in gram-negative bacteria ().
Yamakawa T et al prepared a ganglioside from horse erythrocytes which containedgalactose and neuraminic acid but not hexosamine which they named hematoside(now GM3) ().
Zilch KT et al.
"Cellular and enzymic synthesis of sphingomyelin"
Sphingomyelin is synthesized in the cis Golgi - …
Sphingomyelin is synthesized in the cis ..
SM synthase decreases ceramide a proapoptotic stimulus and increases diacylglycerol an antiapoptotic stimulus.
Sphingomyelin Synthesis in Niemann-Pick Disease
Besides metabolic elongation of 1-OH-group, ceramide can also be degradedby several ceramidases to sphingosine.
Sphingolipid Metabolic Pathway: An Overview of Major …
described a type of membrane lipoproteins, proteolipids, whichare soluble in a mixture of chloroform and methanol ().
First description of the countercurrent separation of "the higher normalfatty acids" (C5-C18) ().
Galactosamine was identified in brain gangliosides ().
First description of the cholesterol lowering effect of a plant sterol (beta-sitosterol)in cholesterol-fed chickens(
Sphingomyelin and sphingomyelin synthase (SMS) …
demonstrated the presence of a "lecithinase C"(now phospholipase C) in the toxin which cleavedphosphorylcholine from lecithin (and sphingomyelin) ().
Klenk E isolated a product from a cerebroside fraction for which he introducedthe name "neuraminic acid" ().
Brückner J described a micro method for the determination of cerebrosides basedon the colorimetric determination of galactose by means of orcinol and sulfuricacid ().
Sphingomyelin and sphingomyelin synthase (SMS) ..
of the synthesisof oleic acid ().
Klenk E identified sphingomyelin as the stored phospholipid in cells frompatients with Niemann-Pick disease ().
Von Euler US identified a lipid-soluble substance from semen which stimulatesuterine smooth muscle contraction and named it prostaglandin ()
Sphingomyelin synthase | Sigma-Aldrich
purified from human erythrocytes a ceramide-based glycolipidcontaining galactosamine but not neuraminic acid which they named globoside ().
The first issue of the journal "Progress in the Chemistry of Fats and other Lipids"appeared that year.
Search results for Sphingomyelin synthase at Sigma-Aldrich
showed that the catalytic hydrogenation of oleate generatednew fatty acids which resulted from both geometrical and positionalisomerization ().
Bloor WR established that phospholipids and sphingolipids are efficientlyextracted using a mixture of ethanol and ether (3/1) (
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