Anti-DPP8 antibody - Spacer region (ab42076)

Relevance

DPP8 (Dipeptidyl Peptidase-8) is a serine proteinase of the clan SC. The clan SC proteinases have a catalytic triad of Ser-Asp-His, and like other Serine proteinases, the active site serine is in a Gly-Xaa-Ser-Xaa -Gly orientation. DPP8 is a member of a broader family of dipeptidyl peptidases including DPP2, DPP4, FAP/Seprase, DPP6, DPP9, DPP10, which have differing substrate specificity and tissue localizations. DPP8 is most closely related to DPP9, with which it shares 58% identical residues. DPP8 has only 27% identity with DPP4, but seems to have similar substrate specificity. Although DPP4 and FAPa form a surface-bound heterodimer in some cells, and homodimers in others, DPP8 seems to be a cytoplasmic protein. The original publication determined that DPP8 was a monomer, active at neutral pH, and later publications suggest DPP-8 is a homodimer. Substrates include glucagon-like peptide-1, glucagon-like peptide-2, neuropeptide-Y, but with different efficacy relative to DPP4. DPP8 has been found in highest abundance in the testis and placenta, but is found in most tissues. Several different splice variants of DPP8 were seen in the different tissues, with some tissue-specific expression. Four different human sequences are reported to date; 898, 882, 847 and 782 amino acids in length. The longest sequence of human DPP8 has a predicted mass of 103.4 kDa, and pI of 5.42. The 882, 847 and 782 amino acid forms are predicted at 101.4, 97.5 and 89.9 kDa respectively, with pIs of 5.26, 5.55 and 5.07. Another three partial sequences that are alternatively spliced have deletions in the catalytic domain, and may not be catalytically active. Over expression of DPP8 caused decreased viability in cells, but a catalytically dead mutant of DPP8 had the same results, thus some of the DPP8 activity may be non-enzymatic. Two of the splice variants have longer aminotermini (16 AA insert), and this may affect localization in the cell.

Cellular localization

Cytoplasmic

Alternative names

Database links