ROOM TEMPERATURE ESR SPECTRA OF Rhus vernicifera LACCASE AND DERIVATIVES

" Although both the type 1 and type 2 coppers of Rhus vernicifera laccase are fully ESR detectable at 77K,only 30% of the type 2 copper are in the cupric from at room temperature.The residual 70% of the type 2 copper was easily transformed into the ESR detectable from by irradiating the resting enzyme with microwave of 200 mW.The enzyme activity did not change by the irradiation with high-powered microwave,indicating that the type 2 copper can be in both the ESR detectable and ESR undetectable forms in solution.The room temperature ESR spectra of the type 2 copper depleted laccase and of the azide-bound type 3 copper signals were also measured at room temperature and compared with those at 77K."