Bjelke JR

References (3)

Title : Selectivity among dipeptidyl peptidases of the S9b family - Bjelke_2006_Cell.Mol.Biol.(Noisy-le-grand)_52_3
Author(s) : Bjelke JR , Kanstrup AB , Rasmussen HB
Ref : Cellular & Molecular Biology (Noisy-le-grand) , 52 :3 , 2006
Abstract : Dipeptidyl peptidase IV is a serine protease with an indirect role in antihyperglycaemia via degradation of the incretin hormones glucagon-like peptide 1 and glucose-dependent insulinotropic polypeptide. Inhibition of the DPP-IV is thus a potential therapeutic strategy for type 2 diabetes. In this study, we have investigated upon selectivity of dipeptidyl peptidase IV compared to two other members of the S9b family, dipeptidyl peptidase 8 and 9, based on kinetic analyses of the pancreatic peptide hormones neuropeptide Y and peptide YY. We report a striking 250-fold preference for cleavage of neuropeptide Y compared to peptide YY observed for DPP-8/-9, but not for DPP-IV. This difference appears to be linked to differences in the S1' pocket within the active site, particularly via flexibility of the oxyanion stabilizing residue Y547. These aspects are discussed in relation to available protein structures of DPP-IV and data on DPP-IV selective inhibitors.
ESTHER : Bjelke_2006_Cell.Mol.Biol.(Noisy-le-grand)_52_3
PubMedSearch : Bjelke_2006_Cell.Mol.Biol.(Noisy-le-grand)_52_3
PubMedID: 17543192

Title : Dipeptidyl peptidases 8 and 9: specificity and molecular characterization compared with dipeptidyl peptidase IV - Bjelke_2006_Biochem.J_396_391
Author(s) : Bjelke JR , Christensen J , Nielsen PF , Branner S , Kanstrup AB , Wagtmann N , Rasmussen HB
Ref : Biochemical Journal , 396 :391 , 2006
Abstract : Dipeptidyl peptidases 8 and 9 have been identified as gene members of the S9b family of dipeptidyl peptidases. In the present paper, we report the characterization of recombinant dipeptidyl peptidases 8 and 9 using the baculovirus expression system. We have found that only the full-length variants of the two proteins can be expressed as active peptidases, which are 882 and 892 amino acids in length for dipeptidyl peptidase 8 and 9 respectively. We show further that the purified proteins are active dimers and that they show similar Michaelis-Menten kinetics and substrate specificity. Both cleave the peptide hormones glucagon-like peptide-1, glucagon-like peptide-2, neuropeptide Y and peptide YY with marked kinetic differences compared with dipeptidyl peptidase IV. Inhibition of dipeptidyl peptidases IV, 8 and 9 using the well-known dipeptidyl peptidase IV inhibitor valine pyrrolidide resulted in similar K(i) values, indicating that this inhibitor is non-selective for any of the three dipeptidyl peptidases.
ESTHER : Bjelke_2006_Biochem.J_396_391
PubMedSearch : Bjelke_2006_Biochem.J_396_391
PubMedID: 16475979
Gene_locus related to this paper: human-DPP9

Title : Tyrosine 547 constitutes an essential part of the catalytic mechanism of dipeptidyl peptidase IV - Bjelke_2004_J.Biol.Chem_279_34691
Author(s) : Bjelke JR , Christensen J , Branner S , Wagtmann N , Olsen C , Kanstrup AB , Rasmussen HB
Ref : Journal of Biological Chemistry , 279 :34691 , 2004
Abstract : Human dipeptidyl peptidase IV (DPP-IV) is a ubiquitously expressed type II transmembrane serine protease. It cleaves the penultimate positioned prolyl bonds at the N terminus of physiologically important peptides such as the incretin hormones glucagon-like peptide 1 and glucose-dependent insulinotropic peptide. In this study, we have characterized different active site mutants. The Y547F mutant as well as the catalytic triad mutants S630A, D708A, and H740L showed less than 1% wild type activity. X-ray crystal structure analysis of the Y547F mutant revealed no overall changes compared with wild type apoDPP-IV, except the ablation of the hydroxyl group of Tyr(547) and a water molecule positioned in close proximity to Tyr(547). To elucidate further the reaction mechanism, we determined the crystal structure of DPP-IV in complex with diisopropyl fluorophosphate, mimicking the tetrahedral intermediate. The kinetic and structural findings of the tyrosine residue are discussed in relation to the catalytic mechanism of DPP-IV and to the inhibitory mechanism of the 2-cyanopyrrolidine class of potent DPP-IV inhibitors, proposing an explanation for the specificity of this class of inhibitors for the S9b family among serine proteases.
ESTHER : Bjelke_2004_J.Biol.Chem_279_34691
PubMedSearch : Bjelke_2004_J.Biol.Chem_279_34691
PubMedID: 15175333
Gene_locus related to this paper: human-DPP4