The MftA M1W/V29A mutant led to the accumulation of MftA M1W/V29A** product. HPLC analysis of the reactions shows the conversion of MftA M1W/V29A (black) to MftA* (13.7 min) and MftA** (14.1 min). Analyses were carried out on a C4 HPLC column. B, the absorbance spectra of MftA M1W/V29A (black), MftA M1W/V29A* (red), and MftA M1W/V29A** (blue) were similar to what was found for reactions with MftA M1W. C, 1H NMR analysis of MftA M1W/V29A** demonstrated the formation of an αβ-unsaturated indicated by appearance of doublets at ∼6.3 and ∼7.2 ppm (indicated by **). mAu, milliabsorbance units.