Removal of copper from Octopus vulgaris haemocyanin. Preparation of the half-apo and apo derivatives.

The two copper ions bound in the active site of Octopus vulgaris haemocyanin can be removed by cyanide. The two metal ions react with the ligand sequentially. In this paper the preparation of Octopus half-apo-haemocyanin, containing at the active site a single copper ion, is described. Moreover, the conditions to obtain Octopus apo-haemocyanin, containing less than 3% of copper still bound, are given.