label: precorrin-6B + 2 S-adenosyl-L-methionine => precorrin-8X + 2 S-adenosyl-L-homocysteine + CO2 + 3 H(+)
label_lc: precorrin-6b + 2 s-adenosyl-l-methionine => precorrin-8x + 2 s-adenosyl-l-homocysteine + co2 + 3 h(+)