Has both folate hydrolase and N-acetylated-alpha-linked-acidic dipeptidase (NAALADase) activity. Exhibits a dipeptidyl-peptidase IV type activity. Binds 2 Zn(2+) ions per subunit. Required for NAALADase activity. Kidney and liver. Not expressed in the prostate. Belongs to the peptidase M28 family. M28B subfamily.