Samiksha Jaiswal (Editor)

Isochorismate synthase

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EC number
  
5.4.4.2

IntEnz
  
IntEnz view

ExPASy
  
NiceZyme view

CAS number
  
37318-53-9

BRENDA
  
BRENDA entry

KEGG
  
KEGG entry

Isochorismate synthase

Isochorismate synthase (MenF) (EC number 5.4.4.2) catalyzes the first step in the biosynthesis of vitamin K (menaquinone) in Escherichia coli.

Contents

Reaction

Isochorismate synthase is an enzyme that catalyzes the irreversible conversion of chorismate to isochorismate:

Isochorismate synthase is most active at 37 °C and at a pH between 7.5 and 8. It requires Mg2+ as a cofactor, in a concentration between 100 μM and 1 mM. Inhibitors of isochorismate synthase include:

  • (4R,5R)-4-hydroxy-5-(1-carboxyvinyloxy)-cyclohex-1-ene carboxylate
  • (4R,5R)-4-hydroxy-5-carboxymethoxy-cyclohex-1-enecarboxylate
  • (4R,5R)-5-(2-carboxy-allyloxy)-4-hydroxy-cyclohex-1-enecarboxylate
  • (4R,5R,6S)-6-ammonio-5-[(1-carboxylatoethenyl)oxy]-4-hydroxycyclohex-1-ene-1-carboxylate
  • (4R,5R,7R)-5-(1-carboxy-ethoxy)-4-hydroxy-cyclohex-1-enecarboxylate
  • (4R,5R,7S)-5-(1-carboxy-ethoxy)-4-hydroxy-cyclohex-1-enecarboxylate
  • (4R,5S,6S)-4-ammonio-5-[(1-carboxylatoethenyl)oxy]-6-hydroxycyclohex-1-ene-1-carboxylate
  • (4R,5S,6S)-5-[(1-carboxylatoethenyl)oxy]-4,6-dihydroxycyclohex-1-ene-1-carboxylate
  • Cu2+
  • Hg2+
  • K+
  • Mg2+ at concentrations above 1 mM
  • NEM

    • Nomenclature

    Isochorismate synthase, or MenF, belongs to the isomerase enzyme family. More specifically it is classified as an intermolecular transferase because it transfers the hydroxy group of chorismate between carbons. The systematic name of this enzyme is isochorismate hydroxymutase, and the common name is isochorismate synthase. Other names for this enzyme include:

  • Isochorismate mutase
  • Menaquinone-specific isochorismate synthase
  • MenF

    • Vitamin K

    Vitamin K contains a quinone ring that participates in redox reactions. These reactions take place in various organisms such as plants, where electrons are transferred during photosynthesis, humans, where electrons are transferred to modify certain types of proteins, and bacteria, where electrons are transferred during anaerobic respiration.

    Pathways

    MenF is a gene that codes for the isochorismate synthase found in the menaquinone pathway in Escherichia coli, not to be mistaken for the entC gene that codes for the isochorismate synthase found in the enterobacter pathway in Escherichia coli. Isochorismate synthase has several other homologs that are found in other organisms. These include:

    References

    Isochorismate synthase Wikipedia
    (Text) CC BY-SA