title: The utilization of the acyl-CoA and the involvement PDAT and DGAT in the biosynthesis of erucic acid-rich triacylglycerols in Crambe seed oil.
abstract: The triacylglycerol of Crambe abyssinica seeds consist of 95% very long chain (>18 carbon) fatty acids (86% erucic acid; 22:1∆13) in the sn-1 and sn-3 positions. This would suggest that C. abyssinica triacylglycerols are not formed by the action of the phospholipid:diacylglycerol acyltransferase (PDAT), but are rather the results of acyl-CoA:diacylglycerol acyltransferase (DGAT) activity. However, measurements of PDAT and DGAT activities in microsomal membranes showed that C. abyssinica has significant PDAT activity, corresponding to about 10% of the DGAT activity during periods of rapid seed oil accumulation. The specific activity of DGAT for erucoyl-CoA had doubled at 19 days after flowering compared to earlier developmental stages, and was, at that stage, the preferred acyl donor, whereas the activities for 16:0-CoA and 18:1-CoA remained constant. This indicates that an expression of an isoform of DGAT with high specificity for erucoyl-CoA is induced at the onset of rapid erucic acid and oil accumulation in the C. abyssinica seeds. Analysis of the composition of the acyl-CoA pool during different stages of seed development showed that the percentage of erucoyl groups in acyl-CoA was much higher than in complex lipids at all stages of seed development except in the desiccation phase. These results are in accordance with published results showing that the rate limiting step in erucic acid accumulation in C. abyssinica oil is the utilization of erucoyl-CoA by the acyltransferases in the glycerol-3-phosphate pathway.
authors.affiliation: Institute of Biology and Environmental Protection, Pomeranian University in Słupsk, Arciszewskiego 22b, 76-200, Słupsk, Poland.
authors.forename: Tomasz
authors.initials: T
authors.lastname: Furmanek
authors.forename: Kamil
authors.initials: K
authors.lastname: Demski
authors.forename: Walentyna
authors.initials: W
authors.lastname: Banaś
authors.forename: Richard
authors.initials: R
authors.lastname: Haslam
authors.forename: Jonathan
authors.initials: J
authors.lastname: Napier
authors.forename: Sten
authors.initials: S
authors.lastname: Stymne
authors.forename: Antoni
authors.initials: A
authors.lastname: Banaś
mesh_terms: D000217:Acyltransferases / Q000378:metabolism*; D031218:Crambe Plant / Q000201:enzymology; D051048:Diacylglycerol O-Acyltransferase / Q000378:metabolism*; D004883:Erucic Acids / Q000378:metabolism*; D035264:Flowers / Q000201:enzymology; D005994:Glycerophosphates / Q000378:metabolism; D053858:Metabolic Networks and Pathways; D008861:Microsomes / Q000201:enzymology; D010938:Plant Oils / Q000378:metabolism; D012639:Seeds / Q000201:enzymology / Q000378:metabolism; D014280:Triglycerides / Q000096:biosynthesis* / Q000378:metabolism
chemical_list: D004883:Erucic Acids; D005994:Glycerophosphates; D010938:Plant Oils; D014280:Triglycerides; C029620:alpha-glycerophosphoric acid; D000217:Acyltransferases; C426836:phospholipid diacylglycerol acyltransferase; C494881:DGAT1 protein, human; D051048:Diacylglycerol O-Acyltransferase