Reactions of Copper‐Free Hemocyanin from Taiwan Snails with Metal Salts

Abstract

Copper‐free hemocyanin (apohemocyanin, apoHc) from Taiwan snails was prepared by cyanide treatment and the reconstitution of hemocyanin was carried out by treating apoHc with Cu(CH3CN)4ClO4. At pH below 5, the apoHc solution is cloudy. When reconstituted at pH near 6, the ratio of absorbances, A345/ a280, has the normal value 0.21, and rapidly decreases with increase in pH. This indicates that reconstitution is best carried out near pH 6. Addition of fluoride at pH 5.3 and cyanide at pH 5.7 causes a relatively rapid drop in absorbance at 345 nm, a primary reaction followed by a slower secondary process. Comparison of the reactions of native and reconstituted hemocyanins with oxygen, fluoride, and cyanide shows that the reconstitution has been successful. Cadmium and manganese derivatives of hemocyanin have been prepared. The order of affinity of metals to the active site of hemocyanin is: Cu>Mn>Cd.