FIG 6.

Collision-induced dissociation l-carnitinyl-CoA. (A) Extracted ion chromatograms correspond to the protonated form ([M+H]⁺) of l-carnitinyl-CoA at m/z 911.2171 (5-ppm accuracy). (B) Collision-induced dissociation tandem mass spectra (25% normalized collision energy). (1) l-Carnitinyl-CoA from the metabolome of GBB-grown cells. (2) Enzymatic formation of l-carnitinyl-CoA analyzed after 60 min in 100 μl of 20 mM Tris-HCl (pH 8.0) containing 3.9 μg of BcoC and 1.7 μg of BcoD in the presence of 90 μM GBB, 50 μM FAD, and 500 μM FC⁺PF⁻₆. (3) l-Carnitinyl-CoA synthesized by CaiC from E. coli by enzymatic conversion of l-carnitine; 2.6 μg of CaiC was incubated with 5 mM l-carnitine, 200 μM CoA, and 2 mM ATP in 100 μl of 100 mM Tris-HCl (pH 8.0) for 60 min. LC-MS analyses were conducted in the positive ionization mode.