FIGURE 10.

LC/MS analysis of products formed from TrpOOH-mediated oxidation of CBA. A, MS traces of mixture of CBA (0.1 mm) with TrpOOH. Data represent extracted ion chromatograms of species with parent ions with m/z [M + H]⁺ 237.09 and 221.09. B, UPLC traces of a mixture of CBA (0.1 mm) with TrpOOH (0.1 mm) collected using the absorption detector set at 300 nm. Prior to the addition of CBA, the sample of tryptophan (1 mm) was photolyzed in the presence of rose bengal (10 μm), phosphate buffer (50 mm, pH 7.4) over 5 min and, next, preincubated with catalase (100 units/ml) for 5 min. C, profiles of the reactants (i.e. CBA, COH, TrpOOH, and TrpOH) (as indicated). Open symbols, reaction profiles when both CBA and TrpOOH were present in the incubation mixture; solid symbols, reaction profiles upon the absence of CBA or TrpOOH, as indicated.