4-carboxy-2-hydroxymuconate semialdehyde hemiacetal + NADP(+) => 2-oxo-2H-pyran-4,6-dicarboxylate + NADPH + H(+)
4-carboxy-2-hydroxymuconate semialdehyde hemiacetal + nadp(+) => 2-oxo-2h-pyran-4,6-dicarboxylate + nadph + h(+)