all-trans-phytofluene + A <=> all-trans-zeta-carotene + AH2
all-trans-phytofluene + a <=> all-trans-zeta-carotene + ah2
all-trans-phytofluene + A <=> all-trans-zeta-carotene + AH2
all-trans-phytofluene + a <=> all-trans-zeta-carotene + ah2