Abstract
Photosynthetically active chloroplasts retaining high rates of fatty acid synthesis from [1-14C]acetate were purified from leaves of both 16:3 (Solanum nodiflorum, Chenopodium album) and 18:3 plants (Amaranthus lividus, Pisum sativum). A comparison of lipids into which newly synthesized fatty acids were incorporated revealed that, in 18:3 chloroplasts, enzymic activities catalyzing the conversion of phosphatidate to diacylglycerol and of diacylglycerol to monogalactosyl diacylglycerol (MGD) were significantly less active than in 16:3 chloroplasts. In contrast, labeling rates of MGD from UDP-[14C]gal were similar for both types of chloroplasts.
The composition and positional distribution of labeled fatty acids within the glycerides synthesized by isolated 16:3 and 18:3 chloroplasts were similar and in each case only a C18/C16 diacylglycerol backbone was synthesized. In nodiflorum chloroplasts, C18:1/C16:0 MGD assembled de novo was completely desaturated to the C18:3/C16:3 stage.
Whereas newly synthesized C18/C18 MGD could not be detected in any of these chloroplasts if incubated with [14C]acetate after isolation, chloroplasts isolated from acetate-labeled leaves contained MGD with labeled C18 fatty acids at both sn-1 and sn-2 positions. Taken together, these results provide further evidence on an organellar level for the operation of pro- and eucaryotic pathways in the biosynthesis of MGD in different groups of plants.
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Selected References
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- Appelqvist L. A. A simple and convenient procedure for the hydrogenation of lipids on the micro- and nanomole scale. J Lipid Res. 1972 Jan;13(1):146–148. [PubMed] [Google Scholar]
- Frentzen M., Heinz E., McKeon T. A., Stumpf P. K. Specificities and selectivities of glycerol-3-phosphate acyltransferase and monoacylglycerol-3-phosphate acyltransferase from pea and spinach chloroplasts. Eur J Biochem. 1983 Jan 1;129(3):629–636. doi: 10.1111/j.1432-1033.1983.tb07096.x. [DOI] [PubMed] [Google Scholar]
- Hajra A. K. On extraction of acyl and alkyl dihydroxyacetone phosphate from incubation mixtures. Lipids. 1974 Aug;9(8):502–505. doi: 10.1007/BF02532495. [DOI] [PubMed] [Google Scholar]
- Kuhn D. N., Knauf M., Stumpf P. K. Subcellular localization of acetyl-CoA synthetase in leaf protoplasts of Spinacia oleracea. Arch Biochem Biophys. 1981 Jul;209(2):441–450. doi: 10.1016/0003-9861(81)90301-5. [DOI] [PubMed] [Google Scholar]
- Link G., Coen D. M., Bogorad L. Differential expression of the gene for the large subunit of ribulose bisphosphate carboxylase in maize leaf cell types. Cell. 1978 Nov;15(3):725–731. doi: 10.1016/0092-8674(78)90258-1. [DOI] [PubMed] [Google Scholar]
- McKee J. W., Hawke J. C. The incorporation of [14C]acetate into the constituent fatty acids of monogalactosyldiglyceride by isolated spinach chloroplasts. Arch Biochem Biophys. 1979 Oct 1;197(1):322–332. doi: 10.1016/0003-9861(79)90252-2. [DOI] [PubMed] [Google Scholar]
- Mudd J. B., Dezacks R. Synthesis of phosphatidylglycerol by chloroplasts from leaves of Spinacia oleracea L. (spinach). Arch Biochem Biophys. 1981 Jul;209(2):584–591. doi: 10.1016/0003-9861(81)90316-7. [DOI] [PubMed] [Google Scholar]
- Roughan P. G., Holland R., Slack C. R. The role of chloroplasts and microsomal fractions in polar-lipid synthesis from [1-14C]acetate by cell-free preparations from spinach (Spinacia oleracea) leaves. Biochem J. 1980 Apr 15;188(1):17–24. doi: 10.1042/bj1880017. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Roughan P. G., Mudd J. B., McManus T. T., Slack C. R. Linoleate and alpha-linolenate synthesis by isolated spinach (Spinacia oleracea) chloroplasts. Biochem J. 1979 Dec 15;184(3):571–574. doi: 10.1042/bj1840571. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Roughan P. G. Turnover of the glycerolipids of pumpkin leaves. The importence of phosphatidylcholine. Biochem J. 1970 Mar;117(1):1–8. doi: 10.1042/bj1170001. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Sato N., Murata N., Miura Y., Ueta N. Effect of growth temperature on lipid and fatty acid compositions in the blue-green algae, Anabaena variabilis and Anacystis nidulans. Biochim Biophys Acta. 1979 Jan 29;572(1):19–28. [PubMed] [Google Scholar]
- Shine W. E., Mancha M., Stumpf P. K. Fat metabolism in higher plants. The function of acyl thioesterases in the metabolism of acyl-coenzymes A and acyl-acyl carrier proteins. Arch Biochem Biophys. 1976 Jan;172(1):110–116. doi: 10.1016/0003-9861(76)90054-0. [DOI] [PubMed] [Google Scholar]
- Siebertz H. P., Heinz E., Joyard J., Douce R. Labelling in vivo and in vitro of molecular species of lipids from chloroplast envelopes and thylakoids. Eur J Biochem. 1980;108(1):177–185. doi: 10.1111/j.1432-1033.1980.tb04710.x. [DOI] [PubMed] [Google Scholar]
- Slack C. R., Roughan P. G., Terpstra J. Some properties of a microsomal oleate desaturase from leaves. Biochem J. 1976 Apr 1;155(1):71–80. doi: 10.1042/bj1550071. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Slack C. R., Roughan P. G. The kinetics of incorporation in vivo of (14C)acetate and (14C)carbon dioxide into the fatty acids of glycerolipids in developing leaves. Biochem J. 1975 Nov;152(2):217–228. doi: 10.1042/bj1520217. [DOI] [PMC free article] [PubMed] [Google Scholar]