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Proc Natl Acad Sci U S A

Title:		"A pathway for the biosynthesis of straight and branched, odd- and even-length, medium-chain fatty acids in plants"
Author(s):		Kroumova AB; Xie Z; Wagner GJ;
Address:		"Agronomy Department, University of Kentucky, Lexington 40546-0091"
Journal Title:		Proc Natl Acad Sci U S A
Year:		1994
Volume:		91
Issue:		24
Page Number:		11437 - 11441
DOI:		10.1073/pnas.91.24.11437
ISSN/ISBN:		0027-8424 (Print) 1091-6490 (Electronic) 0027-8424 (Linking)
Abstract:		"Pathways and enzymes of fatty acid synthase-mediated, long-even-chain (generally C16-C20) fatty acid synthesis are well studied, and general metabolism involved in short-chain (C4-C7) fatty acid biosynthesis is also understood. In contrast, mechanisms of medium-chain (C8-C14) fatty acid synthesis are unclear. Recent work suggests involvement of chain-elongation-terminating thioesterases in medium-chain fatty acid formation in oilseeds and animals. We have shown that iso- and anteiso-branched and straight, odd- and even-length, short-chain fatty acids esterified in plant-trichome-gland-produced sucrose esters are synthesized by using carbon skeletons provided by modified branched-chain amino acid metabolism/catabolism. The principal enzymes involved are those catalyzing leucine biosynthesis in all organisms and those leading to short-chain alcohols in mutant yeasts and alkyl acids in Clostridium species (products often serving as mammalian pheromones). Here we provide evidence that C10-C12 straight medium-chain and C10-C12 branched medium-chain acyl acids of tomato, C6-C8 straight-chain acyl acids of Petunia, and C6 and C8 branched acyl acids of Nicotiana glutinosa are formed by alpha-ketoacid elongation without participation of fatty acid synthase-mediated reactions or -independent thioesterases. This different metabolism suggests greater integration of amino acid and fatty acid metabolism than previously considered and provides other avenues to study and manipulate not only straight even-length but also odd- and even-length straight and branched medium-chain fatty acid biosynthesis"
Keywords:		Acetyl Coenzyme A/metabolism Fatty Acids/chemistry/*metabolism Oxidation-Reduction Plants/*metabolism;
Notes:		"MedlineKroumova, A B Xie, Z Wagner, G J eng 1994/11/22 Proc Natl Acad Sci U S A. 1994 Nov 22; 91(24):11437-41. doi: 10.1073/pnas.91.24.11437"