Large fragments of human serum albumin.
Large fragments of human serum albumin were produced by treatment of the native protein with pepsin at pH3.5. Published sequences of human albumin [Behrens, Spiekerman & Brown (1975) Fed. Proc. Fed. Am. Soc. Exp. Biol. 34, 591; Meloun, Moravek & Kostka (1975) FEBSLett.58, 134-137]were used to locate the fragments in the primary structure. The fragments support both the sequence and proposed disulphide-linkage pattern (Behrens et al., 1975). As the pH of a solution of albumin is lowered from pH4 to pH3.5, the protein undergoes a reversible conformational change known as the N-F transition. The distribution of large fragments of human albumin digested with pepsin in the above pH region was critically dependent on pH. It appeared that this distribution was dependent on the conformation of the protein at low pH, rather than the activity of pepsin. The yields of the large fragments produced by peptic digestion at different values of pH suggested that the C-terminal region of albumin unfolds or separates from the rest of the molecule during the N-F transition. The similarity of peptic fragments of human and bovine albumin produced under identical conditions supports the proposed similar tertiary structure of these molecules.
D000595:Amino Acid Sequence; D001583:Benzoxazoles; D001963:Bromelains; D002852:Chromatography, Ion Exchange; D003497:Cyclic N-Oxides; D004591:Electrophoresis, Polyacrylamide Gel; D010450:Endopeptidases; D005361:Ficain; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008970:Molecular Weight; D010084:Oxidation-Reduction; D010091:Oximes; D010206:Papain; D010434:Pepsin A; D010446:Peptide Fragments; D011487:Protein Conformation; D012709:Serum Albumin / Q000032:analysis*; D013057:Spectrum Analysis; D013438:Sulfhydryl Compounds; D013439:Sulfhydryl Reagents
D001583:Benzoxazoles; D003497:Cyclic N-Oxides; D010091:Oximes; D010446:Peptide Fragments; D012709:Serum Albumin; D013438:Sulfhydryl Compounds; D013439:Sulfhydryl Reagents; D001963:Bromelains; D010450:Endopeptidases; D010206:Papain; D005361:Ficain; D010434:Pepsin A