all-trans-phytofluene + AH2 => 15-cis-phytoene + A
all-trans-phytofluene + ah2 => 15-cis-phytoene + a
all-trans-phytofluene + AH2 => 15-cis-phytoene + A
all-trans-phytofluene + ah2 => 15-cis-phytoene + a