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ENZYME

ENZYME entry: EC 2.3.1.292

PURL: https://purl.expasy.org/enzyme/EC/2.3.1.292
Accepted Name
(phenol)carboxyphthiodiolenone synthase
Reaction catalysed
  • icosanoyl-[(phenol)carboxyphthiodiolenone synthase] + 2 (S)-methylmalonyl-CoA + 3 malonyl-CoA + 5 NADPH + 10 H(+) = C32-carboxyphthiodiolenone-[(phenol)carboxyphthiodiolenone synthase] + 5 CO2 + 5 NADP(+) + 5 CoA + 2 H2O
  • docosanoyl-[(phenol)carboxyphthiodiolenone synthase] + 2 (S)-methylmalonyl-CoA + 3 malonyl-CoA + 5 NADPH + 10 H(+) = C34-carboxyphthiodiolenone-[(phenol)carboxyphthiodiolenone synthase] + 5 CO2 + 5 NADP(+) + 5 CoA + 2 H2O
  • 19-(4-hydroxyphenyl)nonadecanoyl-[(phenol)carboxyphthiodiolenone synthase] + 2 (S)-methylmalonyl-CoA + 3 malonyl-CoA + 5 NADPH + 10 H(+) = C37-(phenol)carboxyphthiodiolenone-[(phenol)carboxyphthiodiolenone synthase] + 5 CO2 + 5 NADP(+) + 5 CoA + 2 H2O
  • 17-(4-hydroxyphenyl)heptadecanoyl-[(phenol)carboxyphthiodiolenone synthase] + 2 (S)-methylmalonyl-CoA + 3 malonyl-CoA + 5 NADPH + 10 H(+) = C35-(phenol)carboxyphthiodiolenone-[(phenol)carboxyphthiodiolenone synthase] + 5 CO2 + 5 NADP(+) + 5 CoA + 2 H2O
Comment(s)
  • The enzyme, which is a complex of five polyketide synthase proteins, is involved in the synthesis of the lipid core common to phthiocerols and phenolphthiocerols.
  • The first protein, PpsA, can accept either a C18 or C20 long-chain fatty acyl, or a (4-hydroxyphenyl)-C17 or C19 fatty acyl.
  • The substrates must first be adenylated by EC 6.2.1.59, which also loads them onto PpsA.
  • PpsA then extends them using a malonyl-CoA extender unit.
  • The PpsB protein adds the next malonyl-CoA extender unit.
  • The absence of a dehydratase and an enoyl reductase domains in the PpsA and PpsB modules results in the formation of the diol portion of the phthiocerol moiety.
  • PpsC adds a third malonyl unit (releasing a water molecule due to its dehydratase domain), PpsD adds an (R)-methylmalonyl unit, releasing a water molecule, and PpsE adds a second (R)-methylmalonyl unit, without releasing a water molecule.
  • The incorporation of the methylmalonyl units results in formation of two branched methyl groups in the elongated product.
  • The enzyme does not contain a thioesterase domain, and release of the products requires the tesA-encoded type II thioesterase.
Cross-references
Rhea expert-curated reactions2.3.1.292
ExplorEnz2.3.1.292
IUBMB Enzyme Nomenclature2.3.1.292
UniProtKB/Swiss-Prot
Q7TXM0, PPSA_MYCBOP9WQE6, PPSA_MYCTOP9WQE7, PPSA_MYCTU
Q7TXL9, PPSB_MYCBOP9WQE4, PPSB_MYCTOP9WQE5, PPSB_MYCTU
Q7TXL8, PPSC_MYCBOP96202, PPSC_MYCTUQ7TXL7, PPSD_MYCBO
P9WQE2, PPSD_MYCTOP9WQE3, PPSD_MYCTUQ7TXL6, PPSE_MYCBO
P9WQE0, PPSE_MYCTOP9WQE1, PPSE_MYCTU
BRENDA2.3.1.292
MetaCyc2.3.1.292
KEGG Ligand Database for Enzyme Nomenclature2.3.1.292
EC2PDB2.3.1.292
MEDLINEFind literature relating to 2.3.1.292

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