Blood copper and its relationship to the globulins.

Holmberg and Laurell (1948) gave the name " caeruloplasmin " to a blue copper globulin complex which they had isolated from both pig and human blood (1947). It was obtained by ammonium sulphate precipitation and was found to be active as an oxidase against p-phenylenediamine. Tlhey considered it to be an a globulin with a molecular weight of about 150,000. Other workers (Scheinberg and Gitlin, 1952; Beam., 1953; Bearn and Kunkel, 1954a) agreed with these findings and also showed that caeruloplasmin was absent or very greatly reduced in hepatolenticular degeneration. Previously, however, Cohn (1948) had stated that copper in the human serum was combined with /B globulin, and in 1949 Thompson and Watson had shown that 25% of the blood copper was bound to y globulin, 55% to /8 globulin, and only 10% to a globulin. Holmberg and Laurell (1951) obtained good correlation between the levels of copper and of oxidase activity in blood in normal subjects, but this fact seems at variance with the observation that, while the copper in the serum of patients with hepatolenticular degeneration may be reduced by half, yet the oxidase activity may be almost nil. This paper records the results of further experiments designed to elucidate these problems.