Abstract
Pseudomonas blue protein readily loses its copper on dialysis against aqueous potassium cyanide. The apo-blue protein so obtained can recombine stoichiometrically with cupric ion, but not with various other metal ions tested. The reconstructed blue protein possesses the same properties as P. blue protein. The ultra-violet absorption spectrum of P. blue protein undergoes significant changes on oxidation and reduction of the copper atom in the protein molecule.
