Biomaterial Database

Conversion of 1-O-alkyl-2-acyl-sn-glycero-3-phosphocholine to 1-O-alk-1'-enyl-2-acyl-sn-glycero-3-phosphoethanolamine. A novel pathway for the metabolism of ether-linked phosphoglycerides. 1992

J C Strum, and A Emilsson, and R L Wykle, and L W Daniel

Department of Biochemistry, Bowman Gray School of Medicine, Wake Forest University, Winston-Salem, North Carolina 27157-1016.

Madin Darby canine kidney (MDCK) cells convert 1-O-[3H]alkyl-2-acyl-sn-glycero-3-phosphocholine [( 3H]alkylacylGPC) to a product tentatively identified as an ethanolamine-containing phosphoglyceride (PE) (Daniel, L. W., Waite, B. M., and Wykle, R. L. (1986) J. Biol. Chem. 261, 9128-9132). In the present study, analysis of the radiolabeled phosphoglycerides as diradylglycerobenzoate derivatives indicated that [3H] alkylacylGPC was initially converted to 1-O-[3H]alkyl-2-acyl-sn-glycero-3-phosphoethanolamine [( 3H]alkylacylGPE) which was subsequently desaturated to 1-O-[3H]alk-1'-enyl-2-acyl-sn-glycero-3-phosphoethanolamine [( 3H]alkenylacylGPE). The conversion of [3H]/[32P]alkyl-lysoGPC to [3H]alkenylacylGPE indicated that base exchange enzymes were not involved in this pathway. A phosphono analog of alkyl-lysoGPC, resistant to phospholipase D hydrolysis and radiolabeled in the 1-O-alkyl chain was readily incorporated, acylated, and subsequently metabolized to [3H]alkylacylGPC and [3H]alkenylacylGPE. Therefore, the involvement of phospholipase D in the conversion pathway was ruled out. The conversion of [3H]alkylacylGPC or its phosphono analog to [3H]alkenylacylGPE was significantly enhanced by the addition of 100 microM ethanolamine to the culture media, suggesting that [3H]alkylacylglycerol is an intermediate in the cytidine-dependent pathway of PE synthesis. MDCK cell cytosol and microsomes contained no detectable phospholipase C activity. However, incubation of microsomes with CMP resulted in the degradation of [3H]alkylacylGPC and accumulation of [3H]alkylacylglycerol. Furthermore, the addition of CDP-ethanolamine to microsomes following preincubation with CMP, resulted in a decrease in [3H]alkylacylglycerol with a concomitant increase in [3H]alkenylacylGPE. Overall, these results suggest that the reverse reaction of choline phosphotransferase may be responsible for the conversion of alkylacylGPC to alkylacylGPE.

UI	MeSH Term	Description	Entries
D007202	Indicators and Reagents	Substances used for the detection, identification, analysis, etc. of chemical, biological, or pathologic processes or conditions. Indicators are substances that change in physical appearance, e.g., color, at or approaching the endpoint of a chemical titration, e.g., on the passage between acidity and alkalinity. Reagents are substances used for the detection or determination of another substance by chemical or microscopical means, especially analysis. Types of reagents are precipitants, solvents, oxidizers, reducers, fluxes, and colorimetric reagents. (From Grant & Hackh's Chemical Dictionary, 5th ed, p301, p499)	Indicator,Reagent,Reagents,Indicators,Reagents and Indicators
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D008861	Microsomes	Artifactual vesicles formed from the endoplasmic reticulum when cells are disrupted. They are isolated by differential centrifugation and are composed of three structural features: rough vesicles, smooth vesicles, and ribosomes. Numerous enzyme activities are associated with the microsomal fraction. (Glick, Glossary of Biochemistry and Molecular Biology, 1990; from Rieger et al., Glossary of Genetics: Classical and Molecular, 5th ed)	Microsome
D010713	Phosphatidylcholines	Derivatives of PHOSPHATIDIC ACIDS in which the phosphoric acid is bound in ester linkage to a CHOLINE moiety.	Choline Phosphoglycerides,Choline Glycerophospholipids,Phosphatidyl Choline,Phosphatidyl Cholines,Phosphatidylcholine,Choline, Phosphatidyl,Cholines, Phosphatidyl,Glycerophospholipids, Choline,Phosphoglycerides, Choline
D010714	Phosphatidylethanolamines	Derivatives of phosphatidic acids in which the phosphoric acid is bound in ester linkage to an ethanolamine moiety. Complete hydrolysis yields 1 mole of glycerol, phosphoric acid and ethanolamine and 2 moles of fatty acids.	Cephalin,Cephalins,Ethanolamine Phosphoglyceride,Ethanolamine Phosphoglycerides,Ethanolamineglycerophospholipids,Phosphoglyceride, Ethanolamine,Phosphoglycerides, Ethanolamine
D010740	Phospholipases	A class of enzymes that catalyze the hydrolysis of phosphoglycerides or glycerophosphatidates. EC 3.1.-.	Lecithinases,Lecithinase,Phospholipase
D010761	Phosphorus Radioisotopes	Unstable isotopes of phosphorus that decay or disintegrate emitting radiation. P atoms with atomic weights 28-34 except 31 are radioactive phosphorus isotopes.	Radioisotopes, Phosphorus
D002460	Cell Line	Established cell cultures that have the potential to propagate indefinitely.	Cell Lines,Line, Cell,Lines, Cell
D002798	Diacylglycerol Cholinephosphotransferase	An enzyme that catalyzes the synthesis of phosphatidylcholines from CDPcholine and 1,2-diacylglycerols. EC 2.7.8.2.	Cholinephosphotransferase,Phosphorylcholine-Glyceride Transferase,1-alkyl-2-Acetylglycerol Cholinephosphotransferase,CDP-Choline 1,2-Diglyceride Choline Phosphotransferase,CDP-Choline Cholinephosphotransferase,CDP-Diacylglycerol Synthase,Diacylglycerol-CDP Choline Phosphotransferase,PAF Phosphocholinetransferase,Phosphocholinetransferase,Phosphorylcholineglyceride Transferase,CDP Choline 1,2 Diglyceride Choline Phosphotransferase,CDP Choline Cholinephosphotransferase,CDP Diacylglycerol Synthase,Choline Phosphotransferase, Diacylglycerol-CDP,Cholinephosphotransferase, 1-alkyl-2-Acetylglycerol,Cholinephosphotransferase, CDP-Choline,Cholinephosphotransferase, Diacylglycerol,Diacylglycerol CDP Choline Phosphotransferase,Phosphocholinetransferase, PAF,Phosphorylcholine Glyceride Transferase,Phosphotransferase, Diacylglycerol-CDP Choline,Synthase, CDP-Diacylglycerol,Transferase, Phosphorylcholine-Glyceride,Transferase, Phosphorylcholineglyceride
D003600	Cytosol	Intracellular fluid from the cytoplasm after removal of ORGANELLES and other insoluble cytoplasmic components.	Cytosols