title: Reaction rates of superoxide radicals with the essential amino acids.
abstract: Upper limits for the rates of reaction of amino acids with superoxide radicals have been determined spectrophotometrically by the stopped flow method. Rate measurements at 23 degrees C for the reaction of HO2 with amino acids were made in the pH range between 1 and 2; similar measurements for O2- were taken near pH 10. The results show that, overall, amino acids are relatively unreactive toward both HO2 and O2-. Computed second-order rate constants for their interaction with HO2 range from 101 mol-1s-1 for aliphatic amino acids to about 600 1 mol-1s-1. The second-order rate constants for the interaction of amino acids with O2- are smaller and range from 0.1 to about 20 1 mol-1s-1.
mesh_terms: D000601:Amino Acids, Essential; D055598:Chemical Phenomena; D002621:Chemistry; D003545:Cysteine; D005609:Free Radicals; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D010100:Oxygen; D013481:Superoxides
chemical_list: D000601:Amino Acids, Essential; D005609:Free Radicals; D013481:Superoxides; D003545:Cysteine; D010100:Oxygen