Under acidic conditions, in the presence of lysine, functions as a cadaverine:lysine antiporter that facilitates the excretion of cadaverine and the uptake of lysine. cadaverine(in) + L-lysine(out) = cadaverine(out) + L-lysine(in) Belongs to the amino acid-polyamine-organocation (APC) superfamily. Basic amino acid/polyamine antiporter (APA) (TC 2.A.3.2) family.