Wagner, L.L.WagnerKaestner, F.F.KaestnerWolf, R.R.WolfStiller, H.H.StillerHeiser, U.U.HeiserManhart, S.S.ManhartHoffmann, T.T.HoffmannRahfeld, J.-U.J.-U.RahfeldDemuth, H.-U.H.-U.DemuthRothermundt, M.M.RothermundtHörsten, S. vonS. vonHörsten2022-03-052022-03-052016https://publica.fraunhofer.de/handle/publica/24687610.1016/j.npep.2016.02.007Background: Dipeptidyl peptidase 4 (DPP4; EC 3.4.14.5; CD26) is a membrane-bound or shedded serine protease that hydrolyzes dipeptides from the N-terminus of peptides with either proline or alanine at the penultimate position. Substrates of DPP4 include several stress-related neuropeptides implicated in anxiety, depression and schizophrenia. A decline of DPP4-like activity has been reported in sera from depressed patient, but not fully characterized regarding DPP4-like enzymes, therapeutic interventions and protein. Methods: Sera from 16 melancholic- and 16 non-melancholic-depressed patients were evaluated for DPP4-like activities and the concentration of soluble DPP4 protein before and after treatment by anti-depressive therapies. Post-translational modification of DPP4-isoforms and degradation of NPY, Peptide YY (PYY), Galanin-like peptide (GALP), Orexin B (OrxB), OrxA, pituitary adenylate cyclase-activating polypeptide (PACAP) and substance P (SP) were studied in serum and in ex vivo human blood.enjournal article