PURIFICATION AND PROPERTIES OF CRYSTALLINE HUMAN CERULOPLASMIN

Crystalline human ceruloplasmin was prepared from a Cohn's fraction F-IV-1 of normal human pooled plasma, by procedures based on acetone fractionation and chromatography on DEAE-sephadex A-50. Needle-shaped crystals of the human ceruloplasmin showed a single component on ultracentrifugation, electrophoresis and immunoelectrophoresis and had a sedimentation constant of 7.04 S and an electrophoretic mobility of 5.2 × 10^–5 cm² volt^-1 sec^-1. Light scattering of the ceruloplasmin gave a molecular weight of 160,000. Absorption coefficient at 610 nm was E^1%_{1 cm} 0.66, at 280 nm, 14.7 and the ratio E_{610 nm}/E_{280 nm}, 0.045. This protein provided 0.31% copper and contained serine, aspartic acid and valine residues as an amino terminal amino acid and showed an oxidase activity of 62 arbitrary units.