4a-hydroxytetrahydrobiopterin dehydratase

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In enzymology, a 4a-hydroxytetrahydrobiopterin dehydratase (EC is an enzyme that catalyzes the chemical reaction

(6R)-6-(L-erythro-1,2-dihydroxypropyl)-5,6,7,8-tetrahydro-4a- hydroxypterin (6R)-6-(L-erythro-1,2-dihydroxypropyl)-7,8-dihydro-6H-pterin + H2O

Thus, the two substrates of this enzyme are (6R)-6-(L-erythro-1,2-dihydroxypropyl)-5,6,7,8-tetrahydro-4a- and hydroxypterin, whereas its two products are (6R)-6-(L-erythro-1,2-dihydroxypropyl)-7,8-dihydro-6H-pterin and H2O.

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 (6R)-6-(L-erythro-1,2-dihydroxypropyl)-5,6,7,8-tetrahydro-4a-hydroxy pterin hydro-lyase [(6R)-6-(L-erythro-1,2-dihydroxypropyl)-7,8-dihydro-6H-pterin-formin g]. Other names in common use include 4alpha-hydroxy-tetrahydropterin dehydratase, pterin-4alpha-carbinolamine dehydratase, and 4a-hydroxytetrahydrobiopterin hydro-lyase.

Structural studies

As of late 2007, 3 structures have been solved for this class of enzymes, with PDB accession codes 1DCO, 1DCP, and 1RU0.


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  • Blau N, Ghisla S, Heizmann CW (1993). "Phenylalanine hydroxylase-stimulating protein/pterin-4 alpha-carbinolamine dehydratase from rat and human liver Purification, characterization, and complete amino acid sequence". J. Biol. Chem. 268: 4828&ndash, 31. PMID 8444860.

External links

Gene Ontology (GO) codes