Enzyme - Isochorismatase

Alternative Name(s)
  • 2,3-dihydro-2,3-dihydroxybenzoate synthase.

Catalytic Activity

H2O + isochorismate = (2S,3S)-2,3-dihydroxy-2,3-dihydrobenzoate + pyruvate


There are no Cofactors for this Enzyme

Reaction Mechanism

    Isochorismatase, also known as 2,3 dihydro-2,3 dihydroxybenzoate synthase, catalyses the conversion of isochorismate, in the presence of water, to 2,3-dihydroxybenzoate and pyruvate, via the hydrolysis of a vinyl ether, an uncommon reaction in biological systems. Isochorismatase is part of the phenazine biosynthesis pathway. Phenazines are antimicrobial compounds that provide the competitive advantage for certain bacteria.

    The carboxylate of Asp38 acts as a general acid to protonate the substrate, yielding a carbocation/oxocarbonium ion that is then rapidly hydrated to form a hemiketal intermediate, which then decomposes spontaneously to products.
    Catalytic Residues
    AA Uniprot Uniprot Resid PDB PDB Resid
    Asp P0DPB9 38 1nf9 38
    His P0DPB9 37 1nf9 37
    Lys P0DPB9 122 1nf9 122

Reaction Parameters

  • Kinetic Parameters
    Organism KM Value [mM] Substrate Comment
    Escherichia coli 0.015 isochorismate
    Pseudomonas aeruginosa 0.1 isochorismate mutant R54K, pH 7.5, 30°C
  • Temperature

    There are no reaction parameters information for this Enzyme.

  • pH

    There are no reaction parameters information for this Enzyme.

Associated Proteins

Protein name Organism
Isochorismatase Bacillus subtilis (strain 168)
Secreted isochorismatase effector Isc1 Verticillium wilt
Vibriobactin-specific isochorismatase Vibrio cholerae serotype O1 (strain ATCC 39541 / Classical Ogawa 395 / O395)
Probable isochorismatase Vibrio vulnificus (strain CMCP6)
Enterobactin synthase component B Escherichia coli (strain K12)