A theoretical study of the dioxygen activation by glucose oxidase and copper amine oxidase

Rajeev Prabhakar, Per E.M. Siegbahn, Boris F. Minaev

Research output: Contribution to journalArticlepeer-review

40 Scopus citations


Glucose oxidase (GO) and copper amine oxidase (CAO) catalyze the reduction of molecular oxygen to hydrogen peroxide. If a closed-shell cofactor (like FADH2 in GO and topaquinone (TPQ) in CAO) is electron donor in dioxygen reduction, the formation of a closed-shell species (H2O 2) is a spin forbidden process. Both in GO and CAO, formation of a superoxide ion that leads to the creation of a radical pair is experimentally suggested to be the rate-limiting step in the dioxygen reduction process. The present density functional theory (DFT) studies suggest that in GO, the creation of the radical pair induces a spin transition by spin orbit coupling (SOC) in O2 -(rad), whereas in CAO, it is induced by exchange interaction with the paramagnetic metal ion (Cu(II)). In the rate-limiting step, this spin-transition is suggested to transform the O 2 -(rad)-FADH2 +(rad) radical pair in GO and the Cu(II)-TPQ (triplet) species in CAO, from a triplet (T) to a singlet (S) state. For CAO, a mechanism for the O-O bond cleavage step in the biogenesis of TPQ is also suggested.

Original languageEnglish (US)
Pages (from-to)173-178
Number of pages6
JournalBiochimica et Biophysica Acta - Proteins and Proteomics
Issue number1-2
StatePublished - Apr 11 2003
Externally publishedYes


  • Copper amine oxidase
  • Density functional theory
  • Dioxygen activation
  • Glucose oxidase
  • Spin transition

ASJC Scopus subject areas

  • Biochemistry
  • Biophysics
  • Genetics


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