Compound as reactive (1)

3-demethylubiquinol-6 + S-adenosyl-L-methionine → S-adenosyl-L-homocysteine + H⁺ + ubiquinol-6

Compound as product (2)

2 NADPH + 2 S-adenosyl-L-methionine + 2 oxygen + 4-methylsalicylate + H⁺ + all-trans-hexaprenyl diphosphate → 2 H₂O + 2 S-adenosyl-L-homocysteine + 2 NADP⁺ + 3-demethylubiquinol-6 + diphosphate + CO₂

a reduced electron donor + oxygen + 6-methoxy-3-methyl-2-all-trans-hexaprenyl-1,4-benzoquinol → an oxidized electron donor + H₂O + 3-demethylubiquinol-6

Reversible reaction (1)

2 H⁺ + oxygen + 6-methoxy-3-methyl-2-all-trans-hexaprenyl-1,4-benzoquinol ↔ H₂O + 3-demethylubiquinol-6