Abstract: The dissociation and Laccase-catalyzed oxidation of six catechols containing tertbutyl group were investigated spectrophotometrically under pH 6.0～8.0 conditions. The studies show that in the presence of tert-butyl group,not only to bonding of these substrates is improved,but through the influence of the microenvironment effect of laccase,the dissociation of these substrates is promoted and the enzymatic reaction can take place under condition of weak acidity(pH6.0), which is far from the first-order dissociation of these sub-strates. Because of the influence of the characterization of tert-butyl group and the microenvironment effect of laccase, these substrates can be transformed by laccase into corresponding o-quinones at pH6.0,and they have a synthetic value,Moreover,using ESR-spin stabilization technique,the o-semiquinone anion-radicals generated during the enzymatic reaction were trapped in pH6.0,and the superfine structures of the ESRspectra were discussed.The result demonstrate that the Laccase-catalyzed reaction of these substrates underwent the stage of the proton transportation and one-electron oxidation.

Key words: Rhus vernicfera laccase, Catechols containing tert-butyl group, Microenvironment effect, o-Semiquinone anion-radicals, Enzymatic synthesis