Open AccessEther glycerolipids: novel substrates for studying specificity of enzymes involved in glycerolipid biosynthesis in higher plants
Author(s) -
WEBER Nikolaus,
BENNING Hildegard
Publication year - 1985
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1985.tb08656.x
Subject(s) - degree of unsaturation , biosynthesis , ether , alkyl , chemistry , enzyme , biochemistry , phospholipid , stereochemistry , membrane , organic chemistry
Ether glycerolipids, predominantly alkylacylglycerols and alkylacylglycerophosphocholines, are synthesized in photomixotrophic rape ( Brassica napus ) suspension cells from various exogenous monoalkylglycerols. The stereospecific distribution of acyl moieties was studied in these ether glycerolipids with regard to chain‐length and degree of unsaturation of alkyl moieties and compared with the distribution of acyl moieties in the corresponding endogenous acyl glycerolipids. The results show the following: (1) Alkylacylglycerophosphocholines replaced up to one‐half of the corresponding physiological membrane lipids, i.e. diacylglycerophosphocholines, without changing the total amount of cholineglycerophospholipids as compared to untreated cells. (2) The composition of acyl moieties in total lipids of rape cell was practically unaltered by fatty acids derived via oxidative cleavage from the various alkyl moieties of ether glycerolipids. (3) In 1‐ O ‐alkyl‐2‐acylglycerols derived from exogenous alkylglycerols and in endogenous 1,2‐diacylglycerols compositions of acyl moieties were found to be different indicating that different pathways were operative in the biosynthesis of these two neutral glycerolipids. (4) Enzymes involved in synthesizing molecular species of 1‐ O ‐alkyl‐2‐acylglycerophosphocholines or 2‐ O ‐alkyl‐1‐acylglycerophosphocholines as well as 1,2‐diacylglycerophosphocholines showed similar pecificities with regard to chain‐length and degree of unsaturation of both alkyl and corresponding acyl moieties. Thus, ether glycerolipids formed by plant cells from exogenous alkylglycerols are suitable metabolites for studying the specificity of enzymes involved in the biosynthesis of glyerolipids.