Sphingomyelin and ceramide-phosphoethanolamine synthesis by microsomes and plasma membranes from rat liver and brain.
Pulse-chase experiments showed that phosphatidylethanolamine (PE) was the direct precursor for ceramide-phosphoethanolamine, a sphingomyelin analogue, in the same way as phosphatidylcholine was for sphingomyelin. Ceramide-phosphoethanolamine could be identified by incorporation of radioactivity from labeled PE, as well as by its stability in alkaline methanolysis and its ability to be methylated by S-adenosyl-methionine. Ceramide-phosphoethanolamine synthesis from labeled exogenous PE seemed to be independent of exogenous ceramide; it was proportional to the amount of incubated membrane, when taking into account the isotopic dilution of labeled precursor by endogenous PE. Sphingomyelin synthesis, which was demonstrated using natural PC as a substrate, was not possible using dipalmitoyl-PC. The formation of sphingomyelin and ceramide-phosphoethanolamine was demonstrated in microsomes and plasma membranes from rat brain and liver.
D000818:Animals; D001921:Brain / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D002518:Ceramides / Q000096:biosynthesis*; D066298:In Vitro Techniques; D008099:Liver / Q000378:metabolism*; D008745:Methylation; D008861:Microsomes / Q000378:metabolism; D010713:Phosphatidylcholines / Q000378:metabolism; D010714:Phosphatidylethanolamines / Q000096:biosynthesis* / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D013109:Sphingomyelins / Q000096:biosynthesis*; D013347:Subcellular Fractions / Q000378:metabolism
D002518:Ceramides; D010713:Phosphatidylcholines; D010714:Phosphatidylethanolamines; D013109:Sphingomyelins; C020888:1,2-dielaidoylphosphatidylethanolamine