| imidazoleglycerol-phosphate dehydratase | |
| Ec Number: | 4.2.1.19 |
| Cas Number: | 9024-35-5 |
| Go Code: | 0004424 |
| Width: | 250 |
| Symbol: | IGPD |
| Imidazoleglycerol-phosphate dehydratase | |
| Pfam: | PF00475 |
| Pfam Clan: | CL0329 |
| Interpro: | IPR000807 |
| Prosite: | PDOC00738 |
| Scop: | 1rhy |
The enzyme imidazoleglycerol-phosphate dehydratase catalyzes the chemical reaction
D-erythro-1-(imidazol-4-yl)glycerol 3-phosphate
\rightleftharpoons
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.
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.[1] In E. coli, this is the protein encoded by the hisB gene.[2]
Certain compounds that inhibit IGPD have been used as herbicides as animals do not have this protein. One of these inhibitors is 3-Amino-1,2,4-triazole (3-AT), which has also been used as a competitive inhibitor of the product of the yeast HIS3 gene (another IGPD), e.g. in the yeast two-hybrid system.[3] [4]
As of late 2007, 3 structures have been solved for this class of enzymes, with PDB accession codes,, and .[5]