title: Dipeptidyl peptidase 9 has two forms, a broad tissue distribution, cytoplasmic localization and DPIV-like peptidase activity.
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.
authors.affiliation: A.W. Morrow Gastroenterology and Liver Centre, Royal Prince Alfred Hospital, Centenary Institute of Cancer Medicine and Cell Biology and The University of Sydney, Locked Bag No. 6, Newton, New South Wales 2042, Australia.
authors.forename: Katerina
authors.initials: K
authors.lastname: Ajami
authors.forename: Catherine A
authors.initials: CA
authors.lastname: Abbott
authors.forename: Geoffrey W
authors.initials: GW
authors.lastname: McCaughan
authors.forename: Mark D
authors.initials: MD
authors.lastname: Gorrell
mesh_terms: D000243:Adenosine Deaminase / Q000378:metabolism*; D017398:Alternative Splicing; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D003001:Cloning, Molecular; D003593:Cytoplasm / Q000378:metabolism*; D017931:DNA Primers; D018819:Dipeptidyl Peptidase 4; D004152:Dipeptidyl-Peptidases and Tripeptidyl-Peptidases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D006023:Glycoproteins / Q000378:metabolism*; D006801:Humans; D008969:Molecular Sequence Data; D051381:Rats; D017386:Sequence Homology, Amino Acid
chemical_list: D017931:DNA Primers; D006023:Glycoproteins; C471241:DPP9 protein, human; D004152:Dipeptidyl-Peptidases and Tripeptidyl-Peptidases; C042807:DPP4 protein, human; D018819:Dipeptidyl Peptidase 4; D000243:Adenosine Deaminase