Unraveling Substrate Specificity and Catalytic Promiscuity of Aspergillus oryzae Catechol Oxidase. (31st October 2018)

• Record Type: Journal Article
• Authors: Penttinen, Leena; Rutanen, Chiara; Jänis, Janne; Rouvinen, Juha; Hakulinen, Nina
• Is Part Of: Chembiochem. Volume 19:Number 22(2018)
• Page Start: 2348
• Page End: 2352
• Publication Date: 2018-10-31
• Subjects: catechol oxidases -- coupled binuclear copper enzymes -- enzyme mechanisms -- enzyme promiscuity -- mass spectrometry; Biochemistry -- Periodicals; Molecular biology -- Periodicals; Pharmaceutical chemistry -- Periodicals; 572
• DOI: 10.1002/cbic.201800387
• Languages: English
• ISSNs: 1439-4227

Abstract

Abstract: Catechol oxidases and tyrosinases are coupled binuclear copper enzymes that oxidize various o ‐diphenolic compounds to corresponding o ‐quinones. Tyrosinases have an additional monooxygenation ability to hydroxylate monophenol to o ‐diphenol. It is still not clear what causes the difference in the catalytic activities. We solved a complex structure of Aspergillus oryzae catechol oxidase with resorcinol bound into the active site. Catalytic activity of A. oryzae catechol oxidase was studied, for the first time, by high‐resolution FT‐ICR mass spectrometry to shed light on the reaction mechanism. The enzyme was also found to catalyze monooxygenation of small phenolics, which provides a novel perspective for the discussion of differences in the catalytic activity between tyrosinases and catechol oxidases. According to the results, two binding modes for resorcinol are suggested and a reaction mechanism for coupled binuclear copper enzymes is discussed. Abstract : Bonus feature : A fungal catechol oxidase from Aspergillus oryzae was found to possess promiscuous monooxygenation activity. A crystal structure complexed with resorcinol showed the binding of resorcinol in a nonproductive binding mode. The resorcinol is suggested to be differently orientated for monooxygenation. A reaction mechanism of monooxygenation and oxidation for coupled binuclear copper enzymes is proposed.