Dipeptidyl peptidase 9 is an enzyme that in humans is encoded by the DPP9 gene.

This gene encodes a protein that is a member of the S9B family in clan SC of the serine proteases. The protein has been shown to have post-proline dipeptidyl aminopeptidase activity, cleaving Xaa-Pro dipeptides from the N-termini of proteins. Although the activity of this protein is similar to that of dipeptidyl peptidase 4 (DPP4), it does not appear to be membrane bound. In general, dipeptidyl peptidases appear to be involved in the regulation of the activity of their substrates and have been linked to a variety of diseases including type 2 diabetes, obesity and cancer. Several transcript variants of this gene have been described but not fully characterized. [provided by RefSeq, Jul 2008]. Publication Note: This RefSeq record includes a subset of the publications that are available for this gene. Please see the Gene record to access additional publications.
Function: Dipeptidyl peptidase that cleaves off N-terminal dipeptides from proteins having a Pro or Ala residue at position 2.