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