Fig 8.

Protein- and time-dependent cleavage of zeaxanthin and lutein by ferret carotene-9’, 10’-oxygenase (CMO2). Reaction velocity as a function of protein concentration (A) and time (B) is plotted for 3-OH-β-apo-10’-carotenal formation from zeaxanthin cleavage by CMO2. Reaction velocity as a function of protein and time is plotted for 3’-OH-α-apo-10-carotenal (C and D) and 3-OH-β-apo-10’-cartenal (E and F) formation from lutein cleavage by CMO2. For protein-dependent cleavage, zeaxanthin (50 µM) and lutein (50 µM) were incubated with various protein concentrations of cell homogenates expressing ferret CMO2 at 37 °C for 60 min. For time-dependent formation, zeaxanthin (50 µM) and lutein (50 µM) were incubated with ~2 mg of homogenate expressing ferret CMO2 at 37 °C for various time points. Data are the average of two independent experiments performed in duplicate.