Fig. 7.

LC-MS/MS analysis of the GSH conjugate formed during the metabolism of MS. A reaction mixture containing CYP2J2 was incubated with MS in the presence of NADPH and the reactive intermediate was trapped with 10 mM GSH. The GSH conjugate was analyzed by LC-MS as described under Materials and Methods. (A) The full mass spectrum of the MS-GSH conjugate with the MH⁺ ion at m/z 647. (B) The MS/MS spectrum of the MS-GSH conjugate. (C) The proposed structure of the MS-GSH conjugate. The dashed lines indicate the sites of fragmentation. The MS/MS spectrum was obtained in the positive mode and analyzed using the Xcalibur software package.