Inactivation of nitroalkane oxidase upon mutation of the active site base and rescue with a deprotonated substrate

Michael P. Valley, Paul F. Fitzpatrick

Research output: Contribution to journalArticle

20 Scopus citations

Abstract

Mutation of Asp402 in nitroalkane oxidase to Asn or Ala inactivates the enzyme with neutral nitroethane as substrate, but the activity can be rescued with the nitroethane anion. The V/K values of the D402N and D402A enzymes with the nitroethane anion are independent of pH, whereas the V/K values of the wild-type and D402E enzymes are pH dependent with both the protonated and the deprotonated forms of nitroethane. Moreover, although the V/K value of the D402E enzyme with neutral nitroethane is 20-fold less than that of the wild-type enzyme, there is only a 2-fold difference in the V/K values with the nitroethane anion. These results are fully consistent with a primary role for Asp402 as the active site base in nitroalkane oxidase which abstracts the substrate α-proton.

Original languageEnglish (US)
Pages (from-to)8738-8739
Number of pages2
JournalJournal of the American Chemical Society
Volume125
Issue number29
DOIs
StatePublished - Jul 23 2003

ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry

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