The Amino-Acid Sequences of Three Cystine-Free Cyanogen-Bromide Fragments of Human Serum Transferrin

Human serum transferrin is susceptible to modification under elevated glycaemic conditions, such as those encountered in diabetes mellitus. The study of transferrin glycation shows that key amino acid residues undergo glycation, inducing structural alterations that compromise its function as an iron-binding protein.

Download Full-text

Studies of the binding of different iron donors to human serum transferrin and isolation of iron-binding fragments from the N- and C-terminal regions of the protein

Biochemical Journal ◽

10.1042/bj1730543 ◽

1978 ◽

Vol 173 (2) ◽

pp. 543-552 ◽

Cited By ~ 107

Author(s):

R W Evans ◽

J Williams

Keyword(s):

Amino Acid ◽

Human Serum ◽

Terminal Region ◽

The Other ◽

Serum Transferrin ◽

Iron Binding ◽

Proteolytic Digestion ◽

Human Serum Transferrin ◽

Partially Saturated ◽

Peptide Maps

1. Trypsin digestion of human serum transferrin partially saturated with iron(III)-nitrilotriacetate at pH 5.5 or pH 8.5 produces a carbohydrate-containing iron-binding fragment of mol.wt. 43000. 2. When iron(III) citrate, FeCl3, iron (III) ascorabate and (NH4)2SO4,FeSO4 are used as iron donors to saturate the protein partially, at pH8.5, proteolytic digestion yields a fragment of mol.wt. 36000 that lacks carbohydrate. 3. The two fragments differ in their antigenic structures, amino acid compositions and peptide ‘maps’. 4. The fragment with mol.wt. 36000 was assigned to the N-terminal region of the protein and the other to the C-terminal region. 5. The distribution of iron in human serum transferrin partially saturated with various iron donors was examined by electrophoresis in urea/polyacrylamide gels and the two possible monoferric forms were unequivocally identified. 6. The site designated A on human serum transferrin [Harris (1977) Biochemistry 16, 560–564] was assigned to the C-terminal region of the protein and the B site to the N-terminal region. 7. The distribution of iron on transferrin in human plasma was determined.

Download Full-text

Sequence studies concerning human serum transferrin: The primary structure of two cyanogen bromide fragments

FEBS Letters ◽

10.1016/0014-5793(74)80386-8 ◽

1974 ◽

Vol 46 (1-2) ◽

pp. 276-280 ◽

Cited By ~ 7

Author(s):

Jacqueline Jollès ◽

Pierre Charet ◽

Pierre Jollès ◽

Jean Montreuil

Keyword(s):

Human Serum ◽

Primary Structure ◽

Cyanogen Bromide ◽

Serum Transferrin ◽

Human Serum Transferrin

Download Full-text

Purification and characterization of the seven cyanogen bromide fragments of human serum transferrin

Biochemical Journal ◽

10.1042/bj1390163 ◽

1974 ◽

Vol 139 (1) ◽

pp. 163-168 ◽

Cited By ~ 18

Author(s):

Michael R. Sutton ◽

K. Brew

Keyword(s):

Human Serum ◽

Cyanogen Bromide ◽

Polyacrylamide Gel Electrophoresis ◽

Sodium Dodecyl ◽

Gel Filtration ◽

Sedimentation Equilibrium ◽

High Yield ◽

Serum Transferrin ◽

Human Serum Transferrin ◽

Equilibrium Ultracentrifugation

1. Procedures are described for the isolation of seven distinct cyanogen bromide fragments in high yield from human serum transferrin. 2. Cyanogen bromide-cleaved transferrin is separated into three fragments (CN-A, CN-B and CN-C) by gel filtration with Sephadex G-100. 3. Four peptides are obtained from CN-A (the largest fragment) after reduction and carboxamidomethylation, by gel filtration in acidic solvents. Two peptides are similarly obtained from fragment CN-B, whereas fragment CN-C is a single cystine-free peptide. 4. The molecular weights of the seven peptides, as determined by polyacrylamide-gel electrophoresis in the presence of sodium dodecyl sulphate, by sedimentation-equilibrium ultracentrifugation and by sequence studies, range from 3100 to 27000. Together they account for a molecular weight of 76200 for transferrin. 5. The two largest fragments contain the carbohydrate attachment sites of the protein, and the smallest fragment is derived from the N-terminus. 6. The amino acid compositions and N-terminal groups of the fragments are reported and the results compared with those of previous investigations.

Download Full-text