Purification and immunochemical studies of dipeptidyl peptidase IV from bovine kidney.

DPP IV from bovine kidney has been purified and characterized by molecular mass, pI, pH optimum and sensitivity to inhibitors. Polyclonal antibodies to the enzyme protein were used to show the location of dipeptidyl peptidase IV in microvillar membranes of bovine kidney using immunogold labelling by secondary antibody. The same antibodies reacted to DPP IV in Western blots of rat, pig and bovine kidney tissue, but failed to recognise the enzyme in bovine brain. This suggests that dipeptidyl peptidase IV may exist as different organ-specific rather than species-specific proteins.