KOPS - Das Institutionelle Repositorium der Universität Konstanz

pH and kinetic isotope effects in D-amino acid oxidase catalysis : evidence for a concerted mechanism in substrate dehydrogenation via hydride transfer

pH and kinetic isotope effects in D-amino acid oxidase catalysis : evidence for a concerted mechanism in substrate dehydrogenation via hydride transfer

Zitieren

Dateien zu dieser Ressource

Prüfsumme: MD5:4e985f922e55277a6d020277f3430c27

HARRIS, Christopher M., Loredano POLLEGIONI, Sandro GHISLA, 2001. pH and kinetic isotope effects in D-amino acid oxidase catalysis : evidence for a concerted mechanism in substrate dehydrogenation via hydride transfer. In: European Journal of Biochemistry. 268(21), pp. 5504-5520. eISSN 0014-2956

@article{Harris2001kinet-8675, title={pH and kinetic isotope effects in D-amino acid oxidase catalysis : evidence for a concerted mechanism in substrate dehydrogenation via hydride transfer}, year={2001}, doi={10.1046/j.1432-1033.2001.02462.x}, number={21}, volume={268}, journal={European Journal of Biochemistry}, pages={5504--5520}, author={Harris, Christopher M. and Pollegioni, Loredano and Ghisla, Sandro} }

<rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:bibo="http://purl.org/ontology/bibo/" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:dcterms="http://purl.org/dc/terms/" xmlns:xsd="http://www.w3.org/2001/XMLSchema#" > <rdf:Description rdf:about="https://kops.uni-konstanz.de/rdf/resource/123456789/8675"> <dcterms:issued>2001</dcterms:issued> <dcterms:available rdf:datatype="http://www.w3.org/2001/XMLSchema#dateTime">2011-03-24T17:45:36Z</dcterms:available> <dc:date rdf:datatype="http://www.w3.org/2001/XMLSchema#dateTime">2011-03-24T17:45:36Z</dc:date> <dc:language>eng</dc:language> <dc:rights>deposit-license</dc:rights> <dc:creator>Ghisla, Sandro</dc:creator> <dc:contributor>Pollegioni, Loredano</dc:contributor> <dc:format>application/pdf</dc:format> <dc:creator>Harris, Christopher M.</dc:creator> <dc:contributor>Harris, Christopher M.</dc:contributor> <dc:creator>Pollegioni, Loredano</dc:creator> <dcterms:abstract xml:lang="eng">The effects of pH, solvent isotope, and primary isotope replacement on substrate dehydrogenation by Rhodotorula gracilis d-amino acid oxidase were investigated. The rate constant for enzyme-FAD reduction by d-alanine increases ≈ fourfold with pH, reflecting apparent pKa values of ≈ 6 and ≈ 8, and reaches plateaus at high and low pH. Such profiles are observed in all presteady-state and steady-state kinetic experiments, using both d-alanine and d-asparagine as substrates, and are inconsistent with the operation of a base essential to catalysis. A solvent deuterium isotope effect of 3.1 ± 1.1 is observed on the reaction with d-alanine at pH 6; it decreases to 1.2 ± 0.2 at pH 10. The primary substrate isotope effect on the reduction rate with [2-D]d-alanine is 9.1 ± 1.5 at low and 2.3 ± 0.3 at high pH. At pH 6.0, the solvent isotope effect is 2.9 ± 0.8 with [2-D]d-alanine, and the primary isotope effect is 8.4 ± 2.4 in D2O. Thus, primary and solvent kinetic isotope effects (KIEs) are independent of the presence of the other isotope, i.e. the double kinetic isotope effect is the product of the individual KIEs, consistent with a transition state in which rupture of the two bonds of the substrate to hydrogen is concerted. These results support a hydride transfer mechanism for the dehydrogenation reaction in d-amino acid oxidase and argue against the occurrence of any intermediates in the process. A pKa,app of ≈ 8 is interpreted to arise from the microscopic ionization of the substrate amino acid α-amino group, but also includes contributions from kinetic parameters.</dcterms:abstract> <dcterms:rights rdf:resource="https://creativecommons.org/licenses/by-nc-nd/2.0/legalcode"/> <dcterms:title>pH and kinetic isotope effects in D-amino acid oxidase catalysis : evidence for a concerted mechanism in substrate dehydrogenation via hydride transfer</dcterms:title> <dc:contributor>Ghisla, Sandro</dc:contributor> <bibo:uri rdf:resource="http://kops.uni-konstanz.de/handle/123456789/8675"/> <dcterms:bibliographicCitation>First publ. in: European Journal of Biochemistry 268 (2001), 21, pp. 5504-5520</dcterms:bibliographicCitation> </rdf:Description> </rdf:RDF>

Dateiabrufe seit 01.10.2014 (Informationen über die Zugriffsstatistik)

pH_and_kinetic_isotope_effects_in_D_amino_acid_oxidase_catalysis.pdf 117

Das Dokument erscheint in:

deposit-license Solange nicht anders angezeigt, wird die Lizenz wie folgt beschrieben: deposit-license

KOPS Suche


Stöbern

Mein Benutzerkonto