A Comparison of Spectrophotometric and Oxidoreduction Potential Method for Laccase Activity Measurement: Crimson Publishers
A Comparison of Spectrophotometric and Oxidoreduction Potential Method for Laccase Activity Measurement by Rana Mustafa in Research in Medical & Engineering Sciences Polyphenol oxidases (PPOs) oxidize phenolic compounds forming quinones, which undergo non-enzymatic reactions resulting in colored compounds. We studied ferulic acid and catechol oxidation by Myceliophthora thermophila laccases using oxidoreduction potential (ORP or Eh) as a novel method to determine PPO activity compared to the traditional spectrophotometric method. Eh varied time-dependently on ferulic acid and catechol concentrations. Eh increased to a maximum value (Ehmax), then decreased irreversibly proportional with substrate concentration. The ΔEh curves of ferulic acid and catechol oxidation at different concentrations by laccase exhibited two steps substrate oxidation: enzymatic and non-enzymatic; linear segments with increasing and decreasing slopes (rate of ΔEh change). The Km valu...