Possibly involved in the synthesis of a specialized molecule, probably related to a fatty acid, which is essential for mitochondrial respiration. Is essential for oxygen uptake and the presence of cytochromes A and B. a fatty acyl-[ACP] + H(+) + malonyl-[ACP] = a 3-oxoacyl-[ACP] + CO2 + holo-[ACP] Present with 1660 molecules/cell in log phase SD medium. Belongs to the thiolase-like superfamily. Beta-ketoacyl-ACP synthases family.