Malonyl-CoA Q ③缩合 CH2 CH3 KS MT AT ACP R ER HD B酮酰ACP合酶，KS C02 乙酰乙酰ACP CH2 HS KS MT AT ACP R ER HD 8-Ketobutyryl-ACPβ 酮酰ACP合酶，KS ③缩合 乙酰乙酰ACP