(2S)-2-methylbutanoyl-CoA + malonyl-[ACP] + H(+) <=> (4S)-4-methyl-3-oxohexanoyl-[ACP] + CO2 + CoA
(2s)-2-methylbutanoyl-coa + malonyl-[acp] + h(+) <=> (4s)-4-methyl-3-oxohexanoyl-[acp] + co2 + coa
(2S)-2-methylbutanoyl-CoA + malonyl-[ACP] + H(+) <=> (4S)-4-methyl-3-oxohexanoyl-[ACP] + CO2 + CoA
(2s)-2-methylbutanoyl-coa + malonyl-[acp] + h(+) <=> (4s)-4-methyl-3-oxohexanoyl-[acp] + co2 + coa