Oxidative coupling of coumarins catalyzed by laccase.

Laccase (LAC) belongs to the blue multi copper lignolytic oxidase enzymes, and has been regarded as an important tool to produce some important dimers in the application of biotechnology. In this study, sixteen coumarins 1-16 were screened to investigate the catalytic ability of LAC, and three coumarins 6, 7, and 16 could be catalyzed to produce three coumarin derivative coupling with acetone 6a, 7a, and 16a. The potential interaction mechanisms of three coumarins 6, 7, and 16 with LAC were analyzed by molecular docking. The kinetic analyses of catalytic reactions for coumarins 6, 7, and 16 with LAC were performed by using the transformed products 6a, 7a, and 16a as standard substances. Km values of coumarins 6, 7, and 16 were ranged from 0.87 +/- 0.07 mu M to 2.74 +/- 029 mu M, respectively. This finding suggested that LAC was a reliable method to catalyze oxidative coupling. (C) 2019 Elsevier B.V. All rights reserved.