Dipeptidyl peptidase 9 has two forms, a broad tissue distribution, cytoplasmic localization and DPIV-like peptidase activity

• Published in: Biochimica et biophysica acta 2004-07, Vol.1679 (1), p.18-28
• Main Authors: Ajami, Katerina, Abbott, Catherine A, McCaughan, Geoffrey W, Gorrell, Mark D
• Format: Article
• Language: English
• Subjects: Adenosine Deaminase - metabolism; Alternative Splicing; Amino Acid Sequence; Animals; Base Sequence; CD26; Cell Line; Cloning, Molecular; Cytoplasm - metabolism; Dipeptidyl peptidase; Dipeptidyl Peptidase 4; Dipeptidyl-Peptidases and Tripeptidyl-Peptidases - chemistry; Dipeptidyl-Peptidases and Tripeptidyl-Peptidases - genetics; Dipeptidyl-Peptidases and Tripeptidyl-Peptidases - metabolism; DNA Primers; Fibroblast activation protein; Gene expression; Glycoproteins - metabolism; Humans; Molecular Sequence Data; Prolyl oligopeptidase; Rats; Sequence Homology, Amino Acid; Serine proteinase
• ISSN: 0167-4781; 0006-3002; 1879-2634
• DOI: 10.1016/j.bbaexp.2004.03.010

Dipeptidyl peptidase (DP) IV has a distinct substrate specificity in hydrolyzing a post-proline bond. Here we present novel data on the sizes and tissue distribution of human and rat gene products and the peptidase activity of the DPIV-related gene DP9. A short cDNA of 2589 bp and a long cDNA of 3006 bp of DP9 were cloned. A ubiquitous predominant DP9 mRNA transcript at 4.4 kb represented the short form, whereas a less abundant 5.0-kb transcript present predominantly in muscle represented the long form. Both forms of DP9 have no transmembrane domain and two potential N-linked glycosylation sites. DP9 exhibited post-proline dipeptidyl aminopeptidase activity and was a cytoplasmic, 110-kDa monomer. Thus, the six DPIV gene family members have diverse characteristics: only DP9 and DP8 have exclusively cytoplasmic localization and only DP9, DP8, fibroblast activation protein (FAP) and DPIV have peptidase activity.