OBSOLETE. Catalysis of the reactions: ATP + 1D-myo-inositol hexakisphosphate = ADP + 5-diphospho-1D-myo-inositol (1,2,3,4,6)pentakisphosphate, and ATP + 1D-myo-inositol 1,3,4,5,6-pentakisphosphate = ADP + diphospho-1D-myo-inositol tetrakisphosphate (isomeric configuration unknown).