Interactions of purified human ceruloplasmin with Lathyrus odoratus, Lens culinaris and Canavalia ensiformis lectins.

Human ceruloplasmin was isolated from normal serum by fractional polyethylene glycol precipitation and subsequent ion exchange chromatography. The molecular mass determined by ultracentrifugation was 132 kDa and an optical density ratio (A610/A280) of 0.046 was observed in the preparation. Immunoelectrophoresis, agarose-gel electrophoresis and N-terminal amino-acid sequence analyses showed that the ceruloplasmin preparation was highly purified, while dodecyl sulphate polyacrylamide-gel electrophoresis indicated some degradation of the protein. Affinity chromatography showed that only a fraction of ceruloplasmin was bound to Lens culinaris or Lathyrus odoratus lectin-Sepharose, whereas nearly all the protein was bound to Canavalia ensiformis lectin-Sepharose. The carbohydrate composition of the ceruloplasmin fractions was analysed. It is suggested that fucose might be a determinant for the microheterogeneity in the carbohydrate chains of ceruloplasmin.