FIG 7.

acI-Blh is a β-carotene oxygenase that catalyzes retinal formation. (A) HPLC-MS data for Pa-EBIY/acI-Blh extract (black) and a retinal standard (yellow). The inset depicts MS/MS data from all-trans peak retention times. (B) HPLC-MS and MS/MS (inset) data for the same experimental extract but with standard retinol spectra (purple). Retinol forms a dehydrated species in positive mode, and the species was used as a proxy for retinol detection (C) Spectra of a control extract subtracted from an extract from cells containing Pantoea ananatis enzymes (CrtE, CrtB, CrtI, and CrtY) and Blh from acI (black), standard retinal (yellow), and standard retinol (purple). All extracts are in ethanol. Insets depict retinal and retinol to highlight conjugation differences, and important maxima are at 379, 324, and 325 nm.