Electronic and magnetic properties of GaSb/Mn and GaAs/Mn digital heterostructures were studied using the augmented plane wave method. The calculated electronic structures of GaSb/Mn and GaAs/Mn are similar. A pre-edge absorption line at 6541 eV should be observed in Mn K-edge x-ray absorption spectra of the heterostructures. This line can be used to study the spatial distribution of Mn in layers. The energy of exchange interaction between two Mn layers was calculated as a function of interlayer separation. Different dependencies of the exchange energy are found for GaSb/Mn and GaAs/Mn heterostructures.