title: Purification and characterization of human prolyl dipeptidase DPP8 in Sf9 insect cells.
abstract: DPP8 is a new member of the prolyl dipeptidases, many of which have important biological functions in vivo. DPP8 catalyzes the cleavage at the carboxyl side of the proline residue at the penultimate position. To study its structure and biochemical properties, we have overexpressed the human DPP8 protein in baculovirus infected Sf9 cells. The protein is soluble and can be purified to homogeneity. Using the chromogenic H-Gly-Pro-pNA as the substrate, a kinetic study shows that purified DPP8 is active and has a similar kcat value as that of DPP-IV, a prolyl dipeptidase that is a drug target for type II diabetes. The kinetic constants of DPP8 are also determined for other chromogenic substrates, and the results indicate that DPP8 has substrate preference at both the P1 and P2 sites. The expression system provides means of better understanding the structure, catalytic mechanism, and biological function of DPP8 protein.
authors.affiliation: Division of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Nankang, Taipei, Taiwan, ROC.
authors.forename: Yuan-Shou
authors.initials: YS
authors.lastname: Chen
authors.forename: Chia-Hui
authors.initials: CH
authors.lastname: Chien
authors.forename: Chandra M
authors.initials: CM
authors.lastname: Goparaju
authors.forename: John Tsu-An
authors.initials: JT
authors.lastname: Hsu
authors.forename: Po-Huang
authors.initials: PH
authors.lastname: Liang
authors.forename: Xin
authors.initials: X
authors.lastname: Chen
mesh_terms: D000818:Animals; D016367:Baculoviridae / Q000235:genetics / Q000378:metabolism; D002460:Cell Line; D004150:Dipeptidases / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism*; D006801:Humans; D007313:Insecta; D010455:Peptides / Q000378:metabolism
chemical_list: D010455:Peptides; D004150:Dipeptidases; C022454:prolyl dipeptidase; C487997:DPP8 protein, human