title: The polypeptide composition of bovine epidermal alpha-keratin.
abstract: 1.  The polypedtide chains that comprise the subunits of the tonofilaments, or th alpha-keratin component, of bovine epidermis were fractionated by combination of chromatography on DEAE-cellulose and preparative polyacrylamide-gel electrophoresis.  2.  The seve polypeptide chains investigated had generalyy similar properties; all contained two residues per molecule of tryptophan and N-acetylserine was the common N-terminal amino acid residue.  3.  On the basis of close similarities in alpha-helix content and amino acid composition, the polypeptide chains were classified into three distinct groups.  Each group contained approximately one-third of the total polypeptides on a molar basis.  The groups and designated polypeptides chain numbers were: group one, polypeptides 1a and 1b, which had moleculae weights of 58,000, contained about 25% alpha-helix, 86 glutamic acid and 8 cysteine residues per molecule, but which differed in net charge, extinction coefficients and tyrosine contents; group two, polypeptides 2, 3, and 4, which hadmolecular weights within thewithin the range of 52,00-56,000, contained about 48% alpha-helix, 54 glutamic acid and 6 cysteine residues per molecule, but which differed in extinction coefficients and tryosine contents; and group, polypeptides 5  and 6, which had molecular weights of 47000-48000, contained about 56% alpha-helix, 64 glutamic acid and 4 cysteine residues per molecule, but which differed in extinction coefficients and tyrosine contents...
mesh_terms: D000596:Amino Acids / Q000032:analysis; D000818:Animals; D001665:Binding Sites; D002417:Cattle; D002845:Chromatography; D002848:Chromatography, DEAE-Cellulose; D004591:Electrophoresis, Polyacrylamide Gel; D007633:Keratins / Q000032:analysis*; D008970:Molecular Weight; D010455:Peptides / Q000032:analysis; D012867:Skin / Q000737:chemistry*; D012967:Sodium Dodecyl Sulfate
chemical_list: D000596:Amino Acids; D010455:Peptides; D012967:Sodium Dodecyl Sulfate; D007633:Keratins