tailieunhanh - Báo cáo khoa học: Metabolic control analysis reveals an important role for diacylglycerol acyltransferase in olive but not in oil palm lipid accumulation

We applied metabolic control analysis to the Kennedy pathway for triacyl-glycerol formation in tissue cultures from the important oil crops, olive (Olea europaeaL.) and oil palm (Elaeis guineensisJacq.). When microsomal fractions were incubated at 30 C rather than 20 C, there was an increase in triacylglycerol labelling. | iFEBS Journal Metabolic control analysis reveals an important role for diacylglycerol acyltransferase in olive but not in oil palm lipid accumulation Umi S. Ramli1 z Joaquin J. Salas1 t Patti A. Quant2 and John L. Harwood1 1 Schoolof Biosciences University of Cardiff UK 2 Department of Biochemistry University of Oxford UK Keywords diacylglycerol acyltransferase lipid accumulation metabolic control analysis oil palm Elaeis guineensis Jacq. olive Olea europaea L. Correspondence J. L. Harwood Schoolof Biosciences Cardiff University Cardiff CF10 3US UK Fax 44 29 2087 4117 Tel. 44 29 2087 4108 E-mail harwood@ Present address Malaysian Palm OilBoard Kuala Lumpur Malaysia We applied metabolic control analysis to the Kennedy pathway for triacylglycerol formation in tissue cultures from the important oil crops olive Olea europaea L. and oil palm Elaeis guineensis Jacq. . When microsomal fractions were incubated at 30 C rather than 20 C there was an increase in triacylglycerol labelling. This increase was accompanied by a build up of diacylglycerol DAG radioactivity in olive but not in oil palm suggesting that the activity of DAG acyltransferase DAGAT was becoming limiting in olive. We used 2-bromooctanoate as a specific inhibitor of DAGAT and showed that the enzyme had a flux control coefficient under the experimental conditions of in olive but only in oil palm. These data revealed important differences in the regulation of lipid biosynthesis in cultures from different plants and suggest that changes in the endogenous activity of DAGAT is unlikely to affect oil accumulation in oil palm crops. tPresent address Instituto de la Grasa Seville Spain Received 1 April2005 revised 2 August 2005 accepted 12 September 2005 doi Oil-producing plants are among the more important agricultural crops. Worldwide w 340 million metric tonnes of oil are produced annually 1 with an emphasis on edible oils but with an increasing production