Human transferrin C: the sequence and cystine bridges of the N-terminal region.

Human transferrin c (76,000 molecular weight) can be cleaved by cyanogen bromide and separated by gel filtration into 4 fractions, CNBr I, II, III, and IV. CNBr II, the smallest cystine containing fragment, can be separated further into 2 fragments of approximately 3,000 and 9,000 daltons by performic acid oxidation; the smaller fragment is the N-terminus of Tf C. The sequence of both fragments, their relationship to each other through cystine bridges, and their relationship within the whole transferrin molecule is given.