DISTRIBUTION OF TRIPEPTIDYL-PEPTIDASE-II IN THE CENTRAL-NERVOUS-SYSTEM OF RAT

Tripeptidyl-peptidase II (TPP II) is a high molecular weight serine pe ptidase which removes tripeptides from a free N-terminus of longer pep tides. Since it had previously been demonstrated that the enzyme can i nactivate enkephalins and dynorphins in vitro by removing the N-termin al Tyr-Gly-Gly peptide, we wanted to see whether TPP II could be invol ved in this process also in vivo. Therefore, the localization of TPP I I in different cerebral regions of rat was investigated by immunoblot analysis and activity measurements. It could be shown that TPP II is r elatively evenly distributed in the central nervous system of rat. Thi s indicates that the physiological role of the enzyme is probably not a specific degradation of enkephalins, but rather pertains to the gene ral turnover of proteins.