KEGG   ENZYME: 2.3.1.300
Entry
EC 2.3.1.300                Enzyme                                 
Name
branched-chain beta-ketoacyl-[acyl-carrier-protein] synthase
Class
Transferases;
Acyltransferases;
Transferring groups other than aminoacyl groups
Sysname
3-methylbutanoyl-CoA:malonyl-[acyl-carrier protein] C-acyltransferase
Reaction(IUBMB)
(1) 3-methylbutanoyl-CoA + a malonyl-[acyl-carrier protein] = a 5-methyl-3-oxohexanoyl-[acyl-carrier-protein] + CoA + CO2 [RN:R12732];
(2) 2-methylpropanoyl-CoA + a malonyl-[acyl-carrier protein] = a 4-methyl-3-oxopentanoyl-[acyl-carrier-protein] + CoA + CO2 [RN:R12733];
(3) (2S)-2-methylbutanoyl-CoA + a malonyl-[acyl-carrier protein] = a (4S)-4-methyl-3-oxohexanoyl-[acyl-carrier-protein] + CoA + CO2 [RN:R12734]
Reaction(KEGG)
R12732 R12733 R12734
Substrate
3-methylbutanoyl-CoA [CPD:C02939];
malonyl-[acyl-carrier protein] [CPD:C01209];
2-methylpropanoyl-CoA [CPD:C00630];
(2S)-2-methylbutanoyl-CoA
Product
5-methyl-3-oxohexanoyl-[acyl-carrier-protein] [CPD:C22368];
CoA [CPD:C00010];
CO2 [CPD:C00011];
4-methyl-3-oxopentanoyl-[acyl-carrier-protein] [CPD:C22369];
(4S)-4-methyl-3-oxohexanoyl-[acyl-carrier-protein] [CPD:C22370]
Comment
The enzyme is responsible for initiating branched-chain fatty acid biosynthesis by the dissociated (or type II) fatty-acid biosynthesis system (FAS-II) in some bacteria, using molecules derived from degradation of the branched-chain amino acids L-leucine, L-valine, and L-isoleucine to form the starting molecules for elongation by the FAS-II system. In some organisms the enzyme is also able to use acetyl-CoA, leading to production of a mix of branched-chain and straight-chain fatty acids [3] (cf. EC 2.3.1.180, beta-ketoacyl-[acyl-carrier-protein] synthase III).
History
EC 2.3.1.300 created 2021
Reference
1  [PMID:9721286]
  Authors
Han L, Lobo S, Reynolds KA
  Title
Characterization of beta-ketoacyl-acyl carrier protein synthase III from Streptomyces glaucescens and its role in initiation of fatty acid biosynthesis.
  Journal
J Bacteriol 180:4481-6 (1998)
DOI:10.1128/JB.180.17.4481-4486.1998
  Sequence
[ag:AAA99447]
Reference
2  [PMID:10629181]
  Authors
Choi KH, Heath RJ, Rock CO.
  Title
beta-ketoacyl-acyl carrier protein synthase III (FabH) is a determining factor in branched-chain fatty acid biosynthesis.
  Journal
J Bacteriol 182:365-70 (2000)
DOI:10.1128/jb.182.2.365-370.2000
Reference
3  [PMID:11375394]
  Authors
Khandekar SS, Gentry DR, Van Aller GS, Warren P, Xiang H, Silverman C, Doyle ML, Chambers PA, Konstantinidis AK, Brandt M, Daines RA, Lonsdale JT.
  Title
Identification, substrate specificity, and inhibition of the Streptococcus pneumoniae beta-ketoacyl-acyl carrier protein synthase III (FabH).
  Journal
J Biol Chem 276:30024-30 (2001)
DOI:10.1074/jbc.M101769200
  Sequence
[spn:SP_0417]
Reference
4  [PMID:19863661]
  Authors
Singh AK, Zhang YM, Zhu K, Subramanian C, Li Z, Jayaswal RK, Gatto C, Rock CO, Wilkinson BJ.
  Title
FabH selectivity for anteiso branched-chain fatty acid precursors in low-temperature adaptation in Listeria monocytogenes.
  Journal
FEMS Microbiol Lett 301:188-92 (2009)
DOI:10.1111/j.1574-6968.2009.01814.x
  Sequence
[lmt:LMRG_01630]
Reference
5  [PMID:27595587]
  Authors
Yu YH, Hu Z, Dong HJ, Ma JC, Wang HH.
  Title
Xanthomonas campestris FabH is required for branched-chain fatty acid and DSF-family quorum sensing signal biosynthesis.
  Journal
Sci Rep 6:32811 (2016)
DOI:10.1038/srep32811
Other DBs
ExplorEnz - The Enzyme Database: 2.3.1.300
IUBMB Enzyme Nomenclature: 2.3.1.300
ExPASy - ENZYME nomenclature database: 2.3.1.300
BRENDA, the Enzyme Database: 2.3.1.300

  All links  
Chemical substance (9)   
   KEGG COMPOUND (9)   
Chemical reaction (4)   
   KEGG REACTION (3)   
   KEGG RCLASS (1)   
Protein sequence (16)   
   UniProt (8)   
   SWISS-PROT (8)   
Protein domain (4)   
   InterPro (4)   
All databases (33)   

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