FIG. 4.

HPLC analyses of the in vitro assay products obtained from β-apo-8′-carotenal (I), β-carotene (II), γ-carotene (III), and torulene (IV) and the corresponding UV-visible light spectra (A to D). CarX formed retinal (A) from the four substrates (S). The conversion to retinal led also to the formation of apo-8′,15′-apo-carotene-dial (B) from β-apo-8′-carotenal, acycloretinal (C) from γ-carotene, and 3,4-didehydro-acycloretinal (D) from torulene. The structure of substrates and products is given in Fig. 5.