Magnetic susceptibility of lacquer tree laccase

Magnetic susceptibility measurements at low temperatures show accurately that only two of the four copper ions in Rhus vernicifera laccase are paramagnetic. The non-magnetic ions, previously suggested to be divalent on the basis of reductive titrations, would then form an exchange-coupled two-copper center possibly similar to that proposed for hemocyanin and mushroom tyrosinase. © 1974.