| http://purl.uniprot.org/citations/15533053 | http://www.w3.org/1999/02/22-rdf-syntax-ns#type | http://purl.uniprot.org/core/Journal_Citation |
| http://purl.uniprot.org/citations/15533053 | http://www.w3.org/1999/02/22-rdf-syntax-ns#type | http://purl.uniprot.org/core/Journal_Citation |
| http://purl.uniprot.org/citations/15533053 | http://www.w3.org/1999/02/22-rdf-syntax-ns#type | http://purl.uniprot.org/core/Journal_Citation |
| http://purl.uniprot.org/citations/15533053 | http://www.w3.org/2000/01/rdf-schema#comment | "1H-3-Hydroxy-4-oxoquinaldine 2,4-dioxygenase (Hod) is a cofactor-less dioxygenase belonging to the alpha/beta hydrolase fold family, catalyzing the cleavage of 1H-3-hydroxy-4-oxoquinaldine (I) and 1H-3-hydroxy-4-oxoquinoline (II) to N-acetyl- and N-formylanthranilate, respectively, and carbon monoxide. Bisubstrate steady-state kinetics and product inhibition patterns of HodC, the C69A protein variant of Hod, suggested a compulsory-order ternary-complex mechanism, in which binding of the organic substrate precedes dioxygen binding, and carbon monoxide is released first. The specificity constants, k(cat)/K(m,A) and k(cat)/K(m,O)()2, were 1.4 x 10(8) and 3.0 x 10(5) M(-1) s(-1) with I and 1.2 x 10(5) and 0.41 x 10(5) M(-1) s(-1) with II, respectively. Whereas HodC catalyzes formation of the dianion of its organic substrate prior to dioxygen binding, HodC-H251A does not, suggesting that H251, which aligns with the histidine of the catalytic triad of the alpha/beta hydrolases, acts as general base in catalysis. Investigation of base-catalyzed dioxygenolysis of I by electron paramagnetic resonance (EPR) spectroscopy revealed formation of a resonance-stabilized radical upon exposure to dioxygen. Since in D(2)O spectral properties are not affected, exchangeable protons are not involved, confirming that the dianion is the reactive intermediate that undergoes single-electron oxidation. We suggest that in the ternary complex of the enzyme, direct single-electron transfer from the substrate dianion to dioxygen may occur, resulting in a radical pair. Based on the estimated spin distribution within the radical anion (observed in the model reaction of I), radical recombination may produce a C4- or C2-hydroperoxy(di)anion. Subsequent intramolecular attack would result in the 2,4-endoperoxy (di)anion that may collapse to the reaction products."xsd:string |
| http://purl.uniprot.org/citations/15533053 | http://purl.org/dc/terms/identifier | "doi:10.1021/bi048735u"xsd:string |
| http://purl.uniprot.org/citations/15533053 | http://purl.org/dc/terms/identifier | "doi:10.1021/bi048735u"xsd:string |
| http://purl.uniprot.org/citations/15533053 | http://purl.org/dc/terms/identifier | "doi:10.1021/bi048735u"xsd:string |
| http://purl.uniprot.org/citations/15533053 | http://purl.uniprot.org/core/author | "Kappl R."xsd:string |
| http://purl.uniprot.org/citations/15533053 | http://purl.uniprot.org/core/author | "Kappl R."xsd:string |
| http://purl.uniprot.org/citations/15533053 | http://purl.uniprot.org/core/author | "Kappl R."xsd:string |
| http://purl.uniprot.org/citations/15533053 | http://purl.uniprot.org/core/author | "Fetzner S."xsd:string |
| http://purl.uniprot.org/citations/15533053 | http://purl.uniprot.org/core/author | "Fetzner S."xsd:string |
| http://purl.uniprot.org/citations/15533053 | http://purl.uniprot.org/core/author | "Fetzner S."xsd:string |
| http://purl.uniprot.org/citations/15533053 | http://purl.uniprot.org/core/author | "Frerichs-Deeken U."xsd:string |
| http://purl.uniprot.org/citations/15533053 | http://purl.uniprot.org/core/author | "Frerichs-Deeken U."xsd:string |
| http://purl.uniprot.org/citations/15533053 | http://purl.uniprot.org/core/author | "Frerichs-Deeken U."xsd:string |
| http://purl.uniprot.org/citations/15533053 | http://purl.uniprot.org/core/author | "Huttermann J."xsd:string |
| http://purl.uniprot.org/citations/15533053 | http://purl.uniprot.org/core/author | "Huttermann J."xsd:string |
| http://purl.uniprot.org/citations/15533053 | http://purl.uniprot.org/core/author | "Huttermann J."xsd:string |
| http://purl.uniprot.org/citations/15533053 | http://purl.uniprot.org/core/author | "Ranguelova K."xsd:string |
| http://purl.uniprot.org/citations/15533053 | http://purl.uniprot.org/core/author | "Ranguelova K."xsd:string |
| http://purl.uniprot.org/citations/15533053 | http://purl.uniprot.org/core/author | "Ranguelova K."xsd:string |
| http://purl.uniprot.org/citations/15533053 | http://purl.uniprot.org/core/date | "2004"xsd:gYear |
| http://purl.uniprot.org/citations/15533053 | http://purl.uniprot.org/core/date | "2004"xsd:gYear |
| http://purl.uniprot.org/citations/15533053 | http://purl.uniprot.org/core/date | "2004"xsd:gYear |