Fatty acid synthesis by isolated chromoplasts from the daffodil. [14C]Acetate incorporation and distribution of labelled acids.
Isolated daffodil (Narcissus pseudonarcissus) chromoplasts showed high rates of [14C]acetate incorporation into lipids. The fatty acids synthesized were predominantly palmitic acid (93%). The radioactivity incorporated was shared mainly between long-chain acyl-CoA (25%), free fatty acids (24%), phosphatidic acid (17%), diacylglycerol (15%), and phosphatidycholine (11%). Galactolipids were not labelled. ATP, NaHCO3, and also the structural integrity of the organelles were essential. Omission of exogenous CoA led to a decreased incorporation (49%); under these conditions the label was distributed mainly between free fatty acids (66%) and diacylglycerol (19%). Addition of lysophosphatidylcholine increased the labelling of phosphatidylcholine, whereas addition of glycerol 1-phosphate increased the labelling of phosphatidic acid and diacylglycerol. Acyl-CoA synthetase and acyl thioesterase (acyl-Coa) activities could be demonstrated. The results are discussed in terms of chromoplasts as non-photosynthetic organelles exhibiting high lipid-synthesizing capabilities.
D000085:Acetates / Q000378:metabolism*; D002736:Chloroplasts / Q000378:metabolism* / Q000648:ultrastructure; D005227:Fatty Acids / Q000096:biosynthesis*; D007700:Kinetics; D010743:Phospholipids / Q000096:biosynthesis; D010944:Plants
D000085:Acetates; D005227:Fatty Acids; D010743:Phospholipids