[Study on the interaction of Rhus vernicifera laccase with Hg2+ ion]

The influence of the mixed time of Hg2+ ion and Rhus vernicifera laccase on the oxidation of 5,6-dibromo-2,3-dicyanohydroquinone (DDBQH2) catalyzed by laccase has been studied at pH 4.4 and 30 +/- 0.2 degrees C. Hg2+ ion can activate the catalytic activity of laccase when the mixed time is short. With the extension of the mixed time, the activation is gradually converted into inhibition. The influence of Hg2+ ion on the absorption spectrum of laccase suggests that it may be the substitution that Hg2+ ion displaces Cu(II) from the type 1 site in laccase causing the inhibition of laccase activity.