Pulsed electron paramagnetic resonance studies of types I and II copper of Rhus vernicifera laccase and porcine ceruloplasmin

Electron spin-echo decay envelopes for types I and II copper of Rhus vernicifera laccase and for type II copper of procine ceruloplasmin have been studied. Nuclear modulation patterns show that imidazole is a ligand for all of them. The linear electric field effect (LEFE) in EPR was studied for type I copper in a laccase preparation from which type II had been removed. The symmetry of the site is near tetrahedral and the magnitude of the LEFE is correlated with the intensity of blue color.