Catalyzes the carboxylation of acetophenone to form 3-oxo-3-phenylpropanoate (benzoylacetate) in the anaerobic catabolism of ethylbenzene. Also carboxylates propiophenone at the same rate and 4-acetyl-pyridine at lower rates. acetophenone + 2 ATP + H2O + hydrogencarbonate = 3-oxo-3-phenylpropanoate + 2 ADP + 2 H(+) + 2 phosphate Divalent metal cations. Magnesium or manganese are required for activity. Inhibited by zinc ions, carbamoylphosphate and beta,gamma-imido-ATP. Kinetic parameters have been established using the heteromeric complex including recombinant Apc5. Acetophenone carboxylase consists of five subunits; a heterooctameric subcomplex of two alpha (Apc1), two beta (Apc2), two gamma (Apc3) and two delta (Apc4) subunits assembles with the epsilon (Apc5) subunit in an unknown stoichiometry.