Analysis of the trapped intermediate in the ALAS-catalyzed reaction of O-methylglycine with succinyl-CoA by LC-MS/MS.
A, UPLC profile of the reaction sample indicating that the retention time of the major species, which has a mass ion spectrum peak at 188.9 m/z, is 0.44 min. B, MS/MS scan spectrum (abundance versus m/z) of the 0.44 min-fraction derived from the reaction sample indicating that the predominant species, with a peak at 188.9 m/z, is consistent with the molecular mass of 189.17 for the predicted intermediate, 5-amino-6-methoxy-4,6-dioxohexanoic acid (inset in A).