title: Specific cyanylation and cleavage at cysteine-104 human hemoglobin alpha-chain. A novel approach to the problem of the alpha-chain tryptic core in the study of haemoglobin variants by "fingerprinting" methods.
abstract: 1. A new approach to the analysis, by "fingerprinting", of the tryptic core region of human haemoglobin alpha-chain is described. 2. The alpha-chain is cyanylated at its single cysteine residue (alpha104) and then split, by exposure to mild alkali, at the N-peptide bond of the resulting beta-thiocyanoalanine residue. 3. The two cleavage fragments, alpha1-103 and alpha104-141, are separated by gel filtration, and the fragment alpha104-141, which contains all the residues of the alpha-chain tryptic core, is digested with pepsin. 4. Preparative "fingerprints" of these peptic peptides yield eight major peptides, which provide complete sequence information for the whole region alpha104-141. 5. The utility of the method is demonstrated by repeating the determination of the substitution in haemoglobin Hopkins-2, a known alpha-chain core variant in which histidine-alpha112 (G19) is replaced by an aspartic acid residue.
mesh_terms: D000409:Alanine; D000595:Amino Acid Sequence; D001224:Aspartic Acid; D003486:Cyanides; D003545:Cysteine; D006454:Hemoglobins / Q000032:analysis*; D006455:Hemoglobins, Abnormal / Q000032:analysis; D006639:Histidine; D006801:Humans; D006868:Hydrolysis; D010434:Pepsin A; D010446:Peptide Fragments / Q000032:analysis; D011487:Protein Conformation; D014357:Trypsin
chemical_list: D003486:Cyanides; D006454:Hemoglobins; D006455:Hemoglobins, Abnormal; D010446:Peptide Fragments; D001224:Aspartic Acid; D006639:Histidine; D014357:Trypsin; D010434:Pepsin A; D003545:Cysteine; D000409:Alanine