FIGURE 10.

BCO2 converts β-cryptoxanthin to β-apo-10′-apocarotenal. A, protein extract containing recombinant murine BCO2 was incubated with increasing concentrations of β-cryptoxanthin. Lipophilic compounds were extracted and subjected to HPLC analysis. Amounts of products (β-apo-10′-carotenal (filled diamonds) and 3-OH-β-apo-10′-carotenal (open squares)) are plotted against the substrate concentration. B, β-cryptoxanthin levels in the liver of 12-week-old female WT, Bco2^−/−, and Bco1^−/− mice. Values indicate means ± S.E. from three animals per genotype. Statistical significance compared with the WT group was tested by the two-tailed Student's t test with p < 0.05 considered significant.