Editing Chloroplast (section)

=== Other chemical products ===

{{expand section|needs more about lipids, also paramylon|date=March 2013}}

The plastid is the site of diverse and complex [[lipid]] synthesis in plants.<ref name="Buchanan BB">Buchanan BB, Gruissem W, Jones RL (Eds.). 2015. Biochemistry & Molecular Biology of Plants. Wiley Blackwell.</ref><ref name="Joyard-2010">{{cite journal | vauthors=Joyard J, Ferro M, Masselon C, Seigneurin-Berny D, Salvi D, Garin J, Rolland N | title=Chloroplast proteomics highlights the subcellular compartmentation of lipid metabolism | journal=Progress in Lipid Research | volume=49 | issue=2 | pages=128–58 | date=April 2010 | pmid=19879895 | doi=10.1016/j.plipres.2009.10.003 }}</ref> The carbon used to form the majority of the lipid is from [[acetyl-CoA]], which is the decarboxylation product of [[pyruvate]].<ref name="Buchanan BB" /> Pyruvate may enter the plastid from the cytosol by passive diffusion through the membrane after production in [[glycolysis]].<ref name="Proudlove-1981">{{cite journal | vauthors=Proudlove MO, Thurman DA | year=1981 | title=The uptake of 2-oxoglutarate and pyruvate by isolated pea chloroplasts | journal=New Phytologist | volume=88 | issue=2| pages=255–264 | doi=10.1111/j.1469-8137.1981.tb01722.x | doi-access=free | bibcode=1981NewPh..88..255P }}</ref> Pyruvate is also made in the plastid from phosphoenolpyruvate, a metabolite made in the cytosol from pyruvate or [[3-Phosphoglyceric acid|PGA]].<ref name="Buchanan BB" /> Acetate in the cytosol is unavailable for lipid biosynthesis in the plastid.<ref name="Bao-2000">Bao X, Focke M, Pollard M, Ohlrogge J. 2000. Understanding in vivo carbon precursor supply for fatty acid synthesis in leaf tissue. Plant Journal 22, 39–50.</ref> The typical length of fatty acids produced in the plastid are 16 or 18 carbons, with 0-3 [[Cis–trans isomerism|cis]] double bonds.<ref name="Ohlrogge-1995">{{cite journal | vauthors=Ohlrogge J, Browse J | year=1995 | title=Lipid Biosynthesis | journal=The Plant Cell | volume=7 | issue=7| pages=957–970 | doi=10.1105/tpc.7.7.957 | pmid=7640528 | pmc=160893 | doi-access=free }}</ref>

The biosynthesis of fatty acids from acetyl-CoA primarily requires two enzymes. Acetyl-CoA carboxylase creates malonyl-CoA, used in both the first step and the extension steps of synthesis. Fatty acid synthase (FAS) is a large complex of enzymes and cofactors including acyl carrier protein (ACP) which holds the acyl chain as it is synthesized. The initiation of synthesis begins with the condensation of malonyl-ACP with acetyl-CoA to produce ketobutyryl-ACP. 2 reductions involving the use of [[NADPH]] and one dehydration creates butyryl-ACP. Extension of the fatty acid comes from repeated cycles of malonyl-ACP condensation, reduction, and dehydration.<ref name="Buchanan BB" />

Other lipids are derived from the [[Non-mevalonate pathway|methyl-erythritol phosphate (MEP) pathway]] and consist of [[Gibberellin|gibberelins]], [[sterols]], [[abscisic acid]], [[phytol]], and innumerable [[secondary metabolite]]s.<ref name="Buchanan BB" />