title: Sensing nitrite through a pseudoazurin-nitrite reductase electron transfer relay.
abstract: Nitrite is converted to nitric oxide by haem or copper-containing enzymes in denitrifying bacteria during the process of denitrification. In designing an efficient biosensor, this enzymic turnover must be quantitatively assessed. The enzyme nitrite reductase from Alcaligenes faecalis contains a redox-active blue copper centre and a nonblue enzyme-active copper centre. It can be covalently tethered to modified gold-electrode surfaces in configurations in which direct electron transfer is possible. A surface cysteine mutant of the enzyme can be similarly immobilised on bare electroactive gold substrates. Under such circumstances, however, electron transfer cannot be effectively coupled with substrate catalytic turnover. In using either the natural redox partner, pseudoazurin, or ruthenium hexammine as an "electron-shuttle" or "conduit" between enzyme and a peptide-modified electrode surface, the coupling of electron transfer to catalysis can be utilised in the development of an amperometric nitrite sensor.
authors.affiliation: Inorganic Chemistry Laboratory, University of Oxford, UK.
authors.forename: Yann
authors.initials: Y
authors.lastname: Astier
authors.forename: Gerard W
authors.initials: GW
authors.lastname: Canters
authors.forename: Jason J
authors.initials: JJ
authors.lastname: Davis
authors.forename: H Allen O
authors.initials: HA
authors.lastname: Hill
authors.forename: Martin P
authors.initials: MP
authors.lastname: Verbeet
authors.forename: Hein J
authors.initials: HJ
authors.lastname: Wijma
mesh_terms: D001400:Azurin / Q000737:chemistry*; D001483:Base Sequence; D017931:DNA Primers; D004563:Electrochemistry; D004579:Electron Transport; D009572:Nitrite Reductases / Q000737:chemistry*; D009573:Nitrites / Q000032:analysis*; D011487:Protein Conformation
chemical_list: D017931:DNA Primers; D009573:Nitrites; C047163:pseudoazurin; D001400:Azurin; D009572:Nitrite Reductases