Component of the acetyl coenzyme A carboxylase (ACC) complex. First, biotin carboxylase catalyzes the carboxylation of biotin on its carrier protein (BCCP) and then the CO(2) group is transferred by the carboxyltransferase to acetyl-CoA to form malonyl-CoA. Does not confer resistance to the endogenous polyketide antibiotic thailandamide, does not confer resistance to thailandamide when expressed in S.typhimurium. acetyl-CoA + N(6)-carboxybiotinyl-L-lysyl-[protein] = malonyl-CoA + N(6)-biotinyl-L-lysyl-[protein] Lipid metabolism; malonyl-CoA biosynthesis; malonyl-CoA from acetyl-CoA: step 1/1. Acetyl-CoA carboxylase is a heterohexamer composed of biotin carboxyl carrier protein (AccB), biotin carboxylase (AccC) and two subunits each of ACCase subunit alpha (AccA) and ACCase subunit beta (AccD). Remains resistant to thailandamide. Belongs to the AccA family.