Sphingolipid base metabolism. Stereospecific uptake of proton in the enzymatic conversion of sphinganine 1-phosphate to ethanolamine 1-phosphate.
D-erythro-(2S, 3R)-Sphinganine 1-phosphate was incubated with rat liver microsomes in the presence of tritiated water. [3H]Ethanolamine 1-phosphate was isolated and converted, through a combination of enzymatic and chemical reactions, to [3H]glycine. The labeled glycine was incubated with D-amino acid oxidase, an enzyme which, in the catalysis of the conversion of glycine to glyoxylic acid, specifically removes the hydrogen in the S configuration at carbon atom 2 of glycine. Essentially complete retention of the labeled hydrogen occurred upon conversion to glyoxylic acid. The combined results indicate that the conversion of D-erythro-(2S,3R)-sphinganine 1-phosphate to palmitaldehyde and ethanolamine 1-phosphate, catalyzed by sphinganine-1-phosphate lyase of rat liver microsomes, proceeds with the stereospecific incorporation of 1 atom of solvent hydrogen into the R configuration of ethanolamine 1-phosphate.
D000818:Animals; D002250:Carbon Radioisotopes; D004983:Ethanolamines / Q000378:metabolism; D005260:Female; D005998:Glycine / Q000378:metabolism; D006038:Glyoxylates / Q000378:metabolism; D007553:Isotope Labeling; D008862:Microsomes, Liver / Q000378:metabolism*; D009943:Organophosphorus Compounds / Q000378:metabolism; D051381:Rats; D013107:Sphingolipids / Q000096:biosynthesis*; D013110:Sphingosine / Q000096:biosynthesis; D013237:Stereoisomerism; D014316:Tritium
D002250:Carbon Radioisotopes; D004983:Ethanolamines; D006038:Glyoxylates; D009943:Organophosphorus Compounds; D013107:Sphingolipids; D014316:Tritium; D013110:Sphingosine; D005998:Glycine