title: Chemical modifications of Escherichia coli penicillin acylase I, tryptophan involvement at the catalytic site.
mesh_terms: D000581:Amidohydrolases / Q000032:analysis*; D001665:Binding Sites; D055598:Chemical Phenomena; D002621:Chemistry; D004926:Escherichia coli / Q000201:enzymology*; D010399:Penicillin Amidase / Q000032:analysis*; D014364:Tryptophan / Q000032:analysis*
chemical_list: D014364:Tryptophan; D000581:Amidohydrolases; D010399:Penicillin Amidase