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Imidazoleglycerol phosphate dehydratase

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EC number
  
4.2.1.19

IntEnz
  
IntEnz view

ExPASy
  
NiceZyme view

CAS number
  
9024-35-5

BRENDA
  
BRENDA entry

KEGG
  
KEGG entry

Imidazoleglycerol-phosphate dehydratase

In enzymology, an imidazoleglycerol-phosphate dehydratase (EC 4.2.1.19) is an enzyme that catalyzes the chemical reaction

D-erythro-1-(imidazol-4-yl)glycerol 3-phosphate 3-(imidazol-4-yl)-2-oxopropyl phosphate + H2O

Hence, this enzyme has one substrate, D-erythro-1-(imidazol-4-yl)glycerol 3-phosphate, and two products, 3-(imidazol-4-yl)-2-oxopropyl phosphate and H2O. This reaction is the sixth step in the biosynthesis of histidine in bacteria, fungi and plants.

This enzyme belongs to the family of lyases, specifically the hydro-lyases, which cleave carbon-oxygen bonds. The systematic name of this enzyme class is D-erythro-1-(imidazol-4-yl)glycerol-3-phosphate hydro-lyase [3-(imidazol-4-yl)-2-oxopropyl-phosphate-forming]. Other names in common use include IGP dehydratase, and D-erythro-1-(imidazol-4-yl)glycerol 3-phosphate hydro-lyase. This enzyme participates in histidine metabolism as it is involved in the 6th step of histidine biosynthesis as part of a nine step cyclical pathway.

IGPD is a recognised novel herbicide target as animals do not have an IGPD

There are two isoforms of IGPD; IGPD1 and IGPD2. The different isoforms are highly conserved with only 8 amino acids differing between them. These subtle differences however affect their activity but as yet it is unknown how.

In most organisms IGPD is a monofunctional protein of about 22 to 29 kD. In some bacteria such as Escherichia coli, it is the C-terminal domain of a bifunctional protein that include a histidinol-phosphatase domain. In E. coli, this is the protein encoded by the hisB gene.

Structural studies

As of late 2007, 3 structures have been solved for this class of enzymes, with PDB accession codes 1RHY, 2AE8, and 2F1D.

References

Imidazoleglycerol-phosphate dehydratase Wikipedia


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