Ajami K, Abbott CA, McCaughan GW, Gorrell MD. Dipeptidyl peptidase 9 has two forms, a broad tissue distribution, cytoplasmic localization and DPIV-like peptidase activity.
ACTA ACUST UNITED AC 2004;
1679:18-28. [PMID:
15245913 DOI:
10.1016/j.bbaexp.2004.03.010]
[Citation(s) in RCA: 97] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2003] [Revised: 03/24/2004] [Accepted: 03/31/2004] [Indexed: 12/21/2022]
Abstract
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.
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