Biochemical studies on human ceruloplasmin.

Ceruloplasmin from nephrotic urine, ascites fluid and plasma has been partially characterized. All ceruloplasmin preparations were found to be comprised of two light and two heavy polypeptide subunits. Characterization of the purified subunits indicated that the alpha chain had a mol. wt. of 16000 and had N-terminal valine while the beta chain had a mol. wt. of 59000 and had N-terminal lysine. All carbohydrate resided in the beta subunit. Incomplete cleavage of the 5-methionine residues of the alpha chain enabled a preliminary ordering of the CNBr fragments. Automated sequence analysis of the alpha chain was carried out and the sequence determined was Val-Phe-Asx-Pro-Arg-Arg-Lys-Leu-Glx-Phe-Ala-Leu-Leu-Phe-Leu-Val-Phe-Asx-Glx-Asx-Glx.