|Superclasses:||Reactions Classified By Conversion Type → Simple Reactions → Chemical Reactions → Protein-Modification Reactions|
|Reactions Classified By Substrate → Macromolecule Reactions → Protein-Reactions → Protein-Modification Reactions|
In Pathway: fatty acid elongation -- saturated
Note that this reaction equation differs from the official Enzyme Commission reaction equations for this EC number.
The direction shown, i.e. which substrates are on the left and right sides, is in accordance with the Enzyme Commission system.
Most BioCyc compounds have been protonated to a reference pH value of 7.3. Please see the PGDB Concepts Guide for more information.
Mass balance status: Marked as unbalanced.
Enzyme Commission Primary Name for 220.127.116.11: β-ketoacyl-[acyl-carrier-protein] synthase I
Enzyme Commission Synonyms for 18.104.22.168: β-ketoacyl-ACP synthase I, β-ketoacyl synthetase, β-ketoacyl-ACP synthetase, β-ketoacyl-acyl carrier protein synthetase, β-ketoacyl-[acyl carrier protein] synthase, β-ketoacylsynthase, condensing enzyme, 3-ketoacyl-acyl carrier protein synthase, fatty acid condensing enzyme, acyl-malonyl(acyl-carrier-protein)-condensing enzyme, acyl-malonyl acyl carrier protein-condensing enzyme, β-ketoacyl acyl carrier protein synthase, 3-oxoacyl-[acyl-carrier-protein] synthase, 3-oxoacyl:ACP synthase I, KASI, KAS I, FabF1, FabB, acyl-[acyl-carrier-protein]:malonyl-[acyl-carrier-protein] C-acyltransferase (decarboxylating)
Enzyme Commission Primary Name for 22.214.171.124: fatty-acid synthase
Enzyme Commission Synonyms for 126.96.36.199: FASN (gene name)
Enzyme Commission Primary Name for 188.8.131.52: fatty-acyl-CoA synthase
Enzyme Commission Synonyms for 184.108.40.206: yeast fatty acid synthase, FAS1 (gene name), FAS2 (gene name)
This reaction is involved in the elongation of fatty acids.
Enzyme Commission Summary for 220.127.116.11:
This enzyme is responsible for the chain-elongation step of dissociated (type II) fatty-acid biosynthesis, i.e. the addition of two C atoms to the fatty-acid chain. Escherichia coli mutants that lack this enzyme are deficient in unsaturated fatty acids. The enzyme can use fatty acyl thioesters of ACP (C2 to C16) as substrates, as well as fatty acyl thioesters of Co-A (C4 to C16) [DAgnolo75]. The substrate specificity is very similar to that of EC 18.104.22.168, β-ketoacyl-ACP synthase II, with the exception that the latter enzyme is far more active with palmitoleoyl-ACP (C16Δ9) as substrate, allowing the organism to regulate its fatty-acid composition with changes in temperature [DAgnolo75, Garwin80].
Enzyme Commission Summary for 22.214.171.124:
The animal enzyme is a multi-functional protein catalysing the reactions of EC 126.96.36.199, [acyl-carrier-protein] S-acetyltransferase, EC 188.8.131.52, [acyl-carrier-protein] S-malonyltransferase, EC 184.108.40.206, β-ketoacyl-[acyl-carrier-protein] synthase I, EC 220.127.116.11, 3-oxoacyl-[acyl-carrier-protein] reductase, EC 18.104.22.168, 3-hydroxyacyl-[acyl-carrier-protein] dehydratase, EC 22.214.171.124, enoyl-[acyl-carrier-protein] reductase (NADPH, Re-specific) and EC 126.96.36.199, oleoyl-[acyl-carrier-protein] hydrolase. cf. EC 188.8.131.52, fatty-acyl-CoA synthase.
Enzyme Commission Summary for 184.108.40.206:
The enzyme from yeasts ( Ascomycota and Basidiomycota) is a multi-functional protein complex composed of two subunits. One subunit catalyses the reactions EC 220.127.116.11, 3-oxoacyl-[acyl-carrier-protein] reductase and EC 18.104.22.168, β-ketoacyl-[acyl-carrier-protein] synthase I, while the other subunit catalyses the reactions of EC 22.214.171.124, [acyl-carrier-protein] S-acetyltransferase, EC 126.96.36.199, [acyl-carrier-protein] S-malonyltransferase, EC 188.8.131.52, 3-hydroxyacyl-[acyl-carrier-protein] dehydratase, EC 184.108.40.206, enoyl-[acyl-carrier-protein] reductase (NADPH, Si-specific) and EC 220.127.116.119, (R)-3-hydroxyacid-ester dehydrogenase. The enzyme differs from the animal enzyme ( EC 18.104.22.168) in that the enoyl reductase domain requires FMN as a cofactor, and the ultimate product is an acyl-CoA (usually palmitoyl-CoA) instead of a free fatty acid.
Relationship Links: BRENDA:EC:22.214.171.124, BRENDA:EC:126.96.36.199, BRENDA:EC:188.8.131.52, ENZYME:EC:184.108.40.206, ENZYME:EC:220.127.116.11, ENZYME:EC:18.104.22.168, IUBMB-ExplorEnz:EC:22.214.171.124, IUBMB-ExplorEnz:EC:126.96.36.199, IUBMB-ExplorEnz:EC:188.8.131.52
Cronan96: Cronan JE Jr., Rock CO (1996). "Biosynthesis of membrane lipids." In: Neidhardt, F.C. (Ed.), Escherichia coli and Salmonella: Cellular and Molecular Biology, 2nd edn, vol. 1, ASM Press, Washington, DC, pp. 612-636.
Garwin80: Garwin JL, Klages AL, Cronan JE (1980). "Structural, enzymatic, and genetic studies of beta-ketoacyl-acyl carrier protein synthases I and II of Escherichia coli." J Biol Chem 1980;255(24);11949-56. PMID: 7002930
Stoops79: Stoops JK, Ross P, Arslanian MJ, Aune KC, Wakil SJ, Oliver RM (1979). "Physicochemical studies of the rat liver and adipose fatty acid synthetases." J Biol Chem 254(15);7418-26. PMID: 457689
Toomey66a: Toomey RE, Wakil SJ (1966). "Studies on the mechanism of fatty acid synthesis. XVI. Preparation and general properties of acyl-malonyl acyl carrier protein-condensing enzyme from Escherichia coli." J Biol Chem 241(5);1159-65. PMID: 5327099
Wang04: Wang H, Cronan JE (2004). "Functional replacement of the FabA and FabB proteins of Escherichia coli fatty acid synthesis by Enterococcus faecalis FabZ and FabF homologues." J Biol Chem 279(33);34489-95. PMID: 15194690
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