Isochorismate synthase

) is an

isomerase Isomerases are a general class of enzymes that convert a molecule from one isomer to another. Isomerases facilitate intramolecular rearrangements in which bonds are broken and formed. The general form of such a reaction is as follows: A–B � ...

enzyme that catalyzes the first step in the biosynthesis of vitamin K₂ (menaquinone) in ''

Escherichia coli ''Escherichia coli'' (),Wells, J. C. (2000) Longman Pronunciation Dictionary. Harlow ngland Pearson Education Ltd. also known as ''E. coli'' (), is a Gram-negative, facultative anaerobic, rod-shaped, coliform bacterium of the genus ''Escher ...

''.

Reaction

Isochorismate synthase, belongs to the isomerase enzyme family. More specifically it is classified as an intramolecular transferase because it transfers the hydroxy group of chorismate between carbons. Isochorismate synthase catalyzes the irreversible conversion of

chorismate Chorismic acid, more commonly known as its anionic form chorismate, is an important biochemical intermediate in plants and microorganisms. It is a precursor for: * The aromatic amino acids phenylalanine, tryptophan, and tyrosine * Indole, indole d ...

to isochorismate: Isochorismate Synthase Rxn

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: * (4''R'',5''R'')-4-hydroxy-5-(1-carboxyvinyloxy)-cyclohex-1-ene carboxylate * (4''R'',5''R'')-4-hydroxy-5-carboxymethoxy-cyclohex-1-enecarboxylate * (4''R'',5''R'')-5-(2-carboxy-allyloxy)-4-hydroxy-cyclohex-1-enecarboxylate * (4''R'',5''R'',6''S'')-6-ammonio-5- 1-carboxylatoethenyl)oxy4-hydroxycyclohex-1-ene-1-carboxylate * (4''R'',5''R'',7''R'')-5-(1-carboxy-ethoxy)-4-hydroxy-cyclohex-1-enecarboxylate * (4''R'',5''R'',7''S'')-5-(1-carboxy-ethoxy)-4-hydroxy-cyclohex-1-enecarboxylate * (4''R'',5''S'',6''S'')-4-ammonio-5- 1-carboxylatoethenyl)oxy6-hydroxycyclohex-1-ene-1-carboxylate * (4''R'',5''S'',6''S'')-5- 1-carboxylatoethenyl)oxy4,6-dihydroxycyclohex-1-ene-1-carboxylate * Cu²⁺ * Hg²⁺ * K⁺ * Mg²⁺ at concentrations above 1 mM * ''N''-ethylmaleimide

Nomenclature

The

systematic name A systematic name is a name given in a systematic way to one unique group, organism, object or chemical substance, out of a specific population or collection. Systematic names are usually part of a nomenclature. A semisystematic name or semitrivial ...

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

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 enterobactin pathway in ''Escherichia coli''. This enzyme catalyzes the first step in the biosynthesis of

salicylic acid Salicylic acid is an organic compound with the formula HOC6H4CO2H. A colorless, bitter-tasting solid, it is a precursor to and a metabolite of aspirin (acetylsalicylic acid). It is a plant hormone, and has been listed by the EPA Toxic Substance ...

in ''

Pseudomonas aeruginosa ''Pseudomonas aeruginosa'' is a common encapsulated, gram-negative, aerobic–facultatively anaerobic, rod-shaped bacterium that can cause disease in plants and animals, including humans. A species of considerable medical importance, ''P. aerugi ...

''. Isochorismate synthase has several other homologs that are found in other organisms. These include:

References

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