1,1'-dihydroxy-1,1',2,2'-tetrahydrolycopene + A <=> 1,1'-dihydroxy-3,4-didehydro-1,2-dihydrolycopene + AH2
1,1'-dihydroxy-1,1',2,2'-tetrahydrolycopene + a <=> 1,1'-dihydroxy-3,4-didehydro-1,2-dihydrolycopene + ah2