Transports acetate. Also able to transport glycolate. Has been isolated from inner membrane preparations as a homodimer. Although ActP belongs to the sodium:solute symporter family, the experiments did not allow to show that acetate transport depends on sodium. The inhibition of acetate transport by the uncoupler CCCP indicates that the driving force used by ActP is a transmembrane electrochemical potential. However, it does not allow to discriminate between hydrogen ion or sodium ion-coupled transporters (PubMed:14563880). Belongs to the sodium:solute symporter (SSF) (TC 2.A.21) family.