Nielsen PF

References (4)

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 : Enhanced insulin secretion and improved glucose tolerance in mice lacking CD26 - Marguet_2000_Proc.Natl.Acad.Sci.U.S.A_97_6874
Author(s) : Marguet D , Baggio L , Kobayashi T , Bernard AM , Pierres M , Nielsen PF , Ribel U , Watanabe T , Drucker DJ , Wagtmann N
Ref : Proc Natl Acad Sci U S A , 97 :6874 , 2000
Abstract : A subset of prolyl oligopeptidases, including dipeptidyl-peptidase IV (DPP IV or CD26, EC ), specifically cleave off N-terminal dipeptides from substrates having proline or alanine in amino acid position 2. This enzyme activity has been implicated in the regulation of the biological activity of multiple hormones and chemokines, including the insulinotropic peptides glucagon-like peptide 1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP). Targeted inactivation of the CD26 gene yielded healthy mice that have normal blood glucose levels in the fasted state, but reduced glycemic excursion after a glucose challenge. Levels of glucose-stimulated circulating insulin and the intact insulinotropic form of GLP-1 are increased in CD26(-/-) mice. A pharmacological inhibitor of DPP IV enzymatic activity improved glucose tolerance in wild-type, but not in CD26(-/-), mice. This inhibitor also improved glucose tolerance in GLP-1 receptor(-/-) mice, indicating that CD26 contributes to blood glucose regulation by controlling the activity of GLP-1 as well as additional substrates. These data reveal a critical role for CD26 in physiological glucose homeostasis, and establish it as a potential target for therapy in type II diabetes.
ESTHER : Marguet_2000_Proc.Natl.Acad.Sci.U.S.A_97_6874
PubMedSearch : Marguet_2000_Proc.Natl.Acad.Sci.U.S.A_97_6874
PubMedID: 10823914

Title : Pancreatic lipase structure-function relationships by domain exchange - Carriere_1997_Biochemistry_36_239
Author(s) : Carriere F , Thirstrup K , Hjorth S , Ferrato F , Nielsen PF , Withers-Martinez C , Cambillau C , Boel E , Thim L , Verger R
Ref : Biochemistry , 36 :239 , 1997
Abstract : We designed chimeric mutants by exchanging the lid domains of the classical human pancreatic lipase (HPL) and the guinea pig pancreatic lipase related protein 2 (GPLRP2). This latter enzyme possesses naturally a large deletion within the lid domain and is not activated by lipid/water interfaces. Furthermore, GPLRP2 exhibits phospholipase A1 and lipase activities in the same order of magnitude, whereas HPL has no significant phospholipase activity and displays a clear interfacial activation. An HPL mutant [HPL(-lid)] with GPLRP2 mini-lid domain does not display interfacial activation. Its specific activity toward triglycerides is, however, dramatically reduced. A GPLRP2 mutant [GPLRP2(+lid)] with HPL full-length lid domain is not interfacially activated, and its lid domain probably exists under a permanent open conformation. Therefore, the phenomenon of interfacial activation in HPL is not only due to the presence of a full-length lid domain but also to other structural elements which probably allow the existence of stabilized closed and open conformations of the lid. GPLRP2(+lid) phospholipase activity is significantly reduced as compared to GPLRP2, whereas its lipase activity remains at the same level. Therefore, the lid domain plays a major role in substrate selectivity and can be considered as part of the active site. However, the presence of a full-length lid domain is not sufficient to explain the absence of phospholipase activity in HPL since HPL(-lid) does not display any phospholipase activity. We also produced a chimeric GPLRP2 mutant in which the C-terminal domain was substituted by the HPL C-terminal domain. The colipase effects, i.e., anchoring and stabilization of the lipase at the interface, are clearly observed with the chimera, whereas GPLRP2 is insensitive to colipase. The kinetic characterization of this chimera reveals for the first time that the interfacial stability of pancreatic lipases depends on the structure of the C-terminal domain.
ESTHER : Carriere_1997_Biochemistry_36_239
PubMedSearch : Carriere_1997_Biochemistry_36_239
PubMedID: 8993339

Title : Cloning and expression in insect cells of two pancreatic lipases and a procolipase from Myocastor coypus - Thirstrup_1995_Eur.J.Biochem_227_186
Author(s) : Thirstrup K , Carriere F , Hjorth SA , Rasmussen PB , Nielsen PF , Ladefoged C , Thim L , Boel E
Ref : European Journal of Biochemistry , 227 :186 , 1995
Abstract : The physiological role of pancreatic lipases has traditionally been assigned solely to triacylglyceride metabolism, while the digestion of phospholipids requires the presence of the pancreatic phospholipase A2, a 14-kDa enzyme unrelated to pancreatic lipases. However, in the guinea pig, it was observed that the pancreatic phospholipase A2 was absent and that a guinea pig pancreatic-lipase-related protein 2 (GPL-RP2) was responsible for phospholipase activity, in contrast to the situation observed in other mammalian species. As the guinea pig is a member of the hystricomorph rodents, it was of interest to investigate if other species within this evolutionary suborder display similar characteristics. The coypu (Myocastor coypus) also a member of the hystricomorph rodents, was chosen for further investigations. The cDNAs encoding two pancreatic lipases and a procolipase from the coypu were cloned, expressed and characterized. One lipase, CoPL-RP2, was identified as belonging to the RP2 subfamily, while the second, CoPL, was found to belong to the classical pancreatic lipase subfamily. Enzymic characterization and sequence data suggest a role for coypu colipase as a specific cofactor for CoPL, while this coypu colipase cannot be an important cofactor for CoPL-RP2 in vivo. Also, the new lipase cDNA sequences were used in a phylogentic analysis to reinvestigate the taxonomical position of the hystricomorph rodents (e.g. coypu and guinea pig) with respect to the myomorph rodents (e.g. rat and mouse).
ESTHER : Thirstrup_1995_Eur.J.Biochem_227_186
PubMedSearch : Thirstrup_1995_Eur.J.Biochem_227_186
PubMedID: 7851384
Gene_locus related to this paper: myoco-1plip , myoco-2plrp