THE BISDING O F COPPER BY IIE,1lOCYANIN GARY FELSI<NFELD W o o d s Dole Ocrano,qrup7tic Z i t ~t i t ~i t ~o i i
Woods Hole, Xasaachusetts
Nan)marine animals acciunulate reinarkably large amounts of copper from sea water, producing a conceiitration of copper within their bodies f a r exceeding that in their external environment (Redfield, '34). Tlie horseslioe crab, Liniulzcs polypli ~i i i u s , and tlie sea conch, Hmsyco?z c amliculatzcm, a r e among the iiiaririe aninials which call accomplish this. They produce Iiluc-colored respiratory pigments, known as hemocyaniiis; thebe cur;-nearly all of tlie copper found in their bodies.
Kobert (Kobert, '03) first obsei*vcd that the addition o f cyanide to oxygenated hemocyanin (oxylicmocyanin) results in the release of oxygen, and the decolorizatioii of the protein. Kuhowitz ('38) showed that this decolorization n7as due to the aliilitj-of the cyanide to form a complex with the copper ions, removing them from the protein. Previous to the work of Knhowitz, Pearson ( '36) had attempted to explain the decolorizatioii 1))postdating the forinatioii of a protein-cyanide com-Illex, or cyano-hemocpnin. A n equilibrium constant was calculated for the postulated reaction. I n view of Kubowitz's discoveries, it scems reasonahle to calculate instead a n equilibrium constant for the dissociation of copper from hemocyanin.
Such a constant has been calculated from a series of experiments in wliicli cyanide, which has a known affinity for cuprous ion, is allowed to compete Rith the protein f o r the metal.