InterPro domain: IPR002469

This domain defines serine peptidases belonging to MEROPS peptidase family S9 (clan SC), subfamily S9B (dipeptidyl-peptidase IV). The protein fold of the peptidase domain for members of this family resembles that of serine carboxypeptidase D, the type example of clan SC. This domain is an alignment of the region to the N-terminal side of the active site, which is found in IPR001375 .

Dipeptidyl-peptidase IV ( 3.4.14.5 ) is also called adenosine deaminase-binding protein (ADA-binding protein) or CD26. The exopeptidase cleaves off N-terminal X-Pro or X-Ala dipeptides from polypeptides (dipeptidyl peptidase IV activity). It serves as the costimulatory molecule in T cell activation and is an associated marker of autoimmune diseases, adenosine deaminase-deficiency and HIV pathogenesis [ 1 , 2 , 3 ].

1. Cloning and functional expression of the T cell activation antigen CD26. J. Immunol. 149, 481-6
2. Adenosine deaminase potentiates the generation of effector, memory, and regulatory CD4+ T cells. J. Leukoc. Biol. 89, 127-36
3. Molecular mechanism and structural basis of interactions of dipeptidyl peptidase IV with adenosine deaminase and human immunodeficiency virus type-1 transcription transactivator. Eur. J. Cell Biol. 91, 265-73