MOLECULAR ASSOCIATION OF HEMOCYANIN PRODUCED BY X-RAYS AS OBSERVED IN THE ULTRACENTRIFUGE

Radiation of hemocyanin: inactivation and reactivation of oxygen-carrying capacity

Oxygen-carrying capacity of hemocyanin from Limulus and Busycotypus (Busycon) decreases with increasing radiation, giving initial yield values for G(-O(2),) of 1.1 and 1.0, respectively. High radiation doses regenerate this capacity of Busycotypus hemocyanin. These effects are attributed largely to the dual nature of hydrogen peroxide, which, at low concentrations, oxidizes protein-bound copper and at high concentrations, that is, at high doses, reduces oxidized copper. The ability of hemocyanin to decompose hydrogen peroxide is relatively unaffected by irradiation, which suggests that copper atoms at the active sites are not all equivalent. The catalase-like activity of Busycotypus hemocyanin can be simulated by amino acid chelates of copper, including arginine, histidine, and glycine.