The enzymatic conversion of cis-[ 14C]phytofluene, trans-[ 14C]phytofluene, and trans-ζ-[ 14C]carotene to poly- cis-acyclic carotenes by a cell-free preparation of tangerine tomato fruit plastids

The conversion of cis-[ 14C]phytofluene to trans-[ 14C]phytofluene and the conversion of the latter to trans-ζ-[ 14C]carotene by a soluble enzyme system obtained from plastids of tangerine tomato fruits is reported. Each of these compounds is also converted to cis-ζ-carotene, proneurosporene, prolycopene, neurosporene, lycopene, and γ- and β-carotenes. [ 14C]Prolycopene was also incubated with the above enzyme system. No conversion of this compound to trans-lycopene or cyclic carotenes was observed. Proof for the formation of the above carotenes from each of the substrates mentioned above was obtained by cochromatography with authentic samples on an alumina column. A close correspondence between radioactivity and light absorbance of each carotene was observed. Further proof for the formation of acyclic and cyclic carotenes from the above radioactive substrates was obtained by gas-liquid chromatography of the hydrogenated products. Coincidence between mass and radioactivity was observed in each case.