Figure 3.

Selected ion chromatogram (bottom) and selected ion spectrum (top) for IAA formed in the enzyme reaction. The sample was purified by C₁₈ HPLC, methylated, and analyzed by GC-MS. Ions at m/z 130 and 189 are characteristic of unlabeled methyl-IAA resulting from unlabeled IAA or indole in the reaction mixture from the plant enzyme preparation. Ions at m/z 132 and 191 are the corresponding ions for the methyl ester from the ¹⁴C-labeled IAA formed from the radioactive indole supplied to the reaction.