title: Bilirubin oxidase label for an enzyme-linked affinity assay with O2 as substrate in a neutral pH NACL solution.
abstract: Laccase, a copper enzyme catalyzing the four-electron reduction of O(2) to water, has been shown by others to be a useful label in enzyme-linked immunoassays, in which the substrate is ambient O(2) instead of an added chemical, such as hydrogen peroxide, or a phosphate ester of a phenol. Laccase-catalyzed O(2) reduction is, however, inhibited by halides, which complex the enzyme's copper ions. Replacement of laccase by bilirubin oxidase, a copper enzyme retaining its maximal activity at high chloride concentrations and at pH 7.2, allows enzyme-amplified affinity assays with O(2) as the substrate in neutral-pH chloride solutions, exemplified here by the assay of DNA, the duplexes of which are unstable at low ionic strength but are stable in strong NaCl solutions.
authors.affiliation: Department of Chemistry, Dankook University, Cheonan, 330-714, Korea.
authors.forename: Hyug-Han
authors.initials: HH
authors.lastname: Kim
authors.forename: Yongchao
authors.initials: Y
authors.lastname: Zhang
authors.forename: Adam
authors.initials: A
authors.lastname: Heller
mesh_terms: D001483:Base Sequence; D002384:Catalysis; D004247:DNA / Q000032:analysis* / Q000737:chemistry; D004563:Electrochemistry; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D006863:Hydrogen-Ion Concentration; D008969:Molecular Sequence Data; D009994:Osmolar Concentration; D044925:Oxidoreductases Acting on CH-CH Group Donors / Q000737:chemistry*; D010100:Oxygen / Q000737:chemistry*; D012965:Sodium Chloride / Q000737:chemistry*; D012996:Solutions / Q000737:chemistry; D014867:Water / Q000737:chemistry
chemical_list: D012996:Solutions; D014867:Water; D012965:Sodium Chloride; D004247:DNA; D044925:Oxidoreductases Acting on CH-CH Group Donors; C042401:bilirubin oxidase; D010100:Oxygen