title: Identification of residue 103 in hen egg-white lysozyme.
abstract: Since it has been uncertain whether residue 103 in hen egg-white lysozyme is aspartic acid or asparagine, we reexamined the identity of this residue. To avoid complication, the tryptic peptide T-13 (Ile 98-Arg 112) was further cleaved. The peptide containing residues Gly 102-Arg 112 was obtained by tryptic digestion of lysozyme modified at Asp 101 with diethylenetriamine. The peptide containing residues Ile 98-homoserine 105 was obtained by BrCN treatment of peptide T-13. Both Edman degradation of the former peptide and carboxypeptidase X digestion of the latter peptide identified residue 103 in hen egg-white lysozyme as asparagine.
mesh_terms: D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D000818:Animals; D001216:Asparagine / Q000032:analysis; D001224:Aspartic Acid / Q000032:analysis; D002268:Carboxypeptidases / Q000378:metabolism; D002645:Chickens; D003488:Cyanogen Bromide; D004529:Egg White / Q000032:analysis*; D009113:Muramidase / Q000032:analysis*; D010446:Peptide Fragments / Q000032:analysis; D014357:Trypsin / Q000378:metabolism
chemical_list: D000596:Amino Acids; D010446:Peptide Fragments; D001224:Aspartic Acid; D001216:Asparagine; D009113:Muramidase; D002268:Carboxypeptidases; C022633:serine carboxypeptidase; D014357:Trypsin; D003488:Cyanogen Bromide