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Unraveling Substrate Specificity and Catalytic Promiscuity of Aspergillus oryzae Catechol Oxidase
Author(s) -
Penttinen Leena,
Rutanen Chiara,
Jänis Janne,
Rouvinen Juha,
Hakulinen Nina
Publication year - 2018
Publication title -
chembiochem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.05
H-Index - 126
eISSN - 1439-7633
pISSN - 1439-4227
DOI - 10.1002/cbic.201800387
Subject(s) - catechol , chemistry , aspergillus oryzae , catechol oxidase , tyrosinase , resorcinol , enzyme , catalysis , oxidase test , stereochemistry , substrate (aquarium) , polyphenol oxidase , organic chemistry , combinatorial chemistry , peroxidase , biology , ecology
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.