title: Sequence of a peptide susceptible to mixed-function oxidation. Probable cation binding site in glutamine synthetase.
abstract: Mixed-function oxidation of glutamine synthetase from Escherichia coli causes loss of catalytic activity. The inactivation correlates with the loss of 1 of 16 histidine residues/subunit (Levine, R.L. (1983) J. Biol. Chem. 258, 11823-11827). A cyanogen bromide peptide containing the oxidizable histidine has been isolated. Within the protein, the sequence is Met-His-Cys-His-Met. This hydrophilic sequence likely forms one of the divalent metal-binding sites of glutamine synthetase. Binding of Fe2+ to this site permits generation of an activated oxygen species which reacts with a nearby histidine residue. This site-specific free radical mechanism accounts for the specificity of the mixed-function oxidation.
authors.forename: J M
authors.initials: JM
authors.lastname: Farber
authors.forename: R L
authors.initials: RL
authors.lastname: Levine
mesh_terms: D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D001224:Aspartic Acid / Q000032:analysis; D002851:Chromatography, High Pressure Liquid; D004926:Escherichia coli / Q000201:enzymology; D005974:Glutamate-Ammonia Ligase / Q000378:metabolism*; D006639:Histidine / Q000032:analysis; D007700:Kinetics; D006899:Mixed Function Oxygenases / Q000378:metabolism*; D010446:Peptide Fragments / Q000302:isolation & purification / Q000378:metabolism*; D014357:Trypsin
chemical_list: D000596:Amino Acids; D010446:Peptide Fragments; D001224:Aspartic Acid; D006639:Histidine; D006899:Mixed Function Oxygenases; D014357:Trypsin; D005974:Glutamate-Ammonia Ligase