title: Inhibition of Pig Phosphoenolpyruvate Carboxykinase Isoenzymes by 3-Mercaptopicolinic Acid and Novel Inhibitors.
abstract: There exist two isoforms of cytosolic phosphoenolpyruvate carboxykinase (PEPCK-C) in pig populations that differ in a single amino acid (Met139Leu). The isoenzymes have different kinetic properties, affecting more strongly the Km and Vmax of nucleotides. They are associated to different phenotypes modifying traits of considerable economic interest. In this work we use inhibitors of phosphoenolpyruvate carboxykinase activity to search for further differences between these isoenzymes. On the one hand we have used the well-known inhibitor 3-mercaptopicolinic acid. Its inhibition patterns were the same for both isoenzymes: a three-fold decrease of the Ki values for GTP in 139Met and 139Leu (273 and 873 μM, respectively). On the other hand, through screening of a chemical library we have found two novel compounds with inhibitory effects of a similar magnitude to that of 3-mercaptopicolinic acid but with less solubility and specificity. One of these novel compounds, (N'1-({5-[1-methyl-5-(trifluoromethyl)-1H-pyrazol-3-yl]-2-thienyl}methylidene)-2,4-dichlorobenzene-1-carbohydrazide), exhibited significantly different inhibitory effects on either isoenzyme: it enhanced threefold the apparent Km value for GTP in 139Met, whereas in 139Leu, it reduced it from 99 to 69 μM. The finding of those significant differences in the binding of GTP reinforces the hypothesis that the Met139Leu substitution affects strongly the nucleotide binding site of PEPCK-C.
authors.affiliation: Departamento de Producción Animal y Ciencia de los Alimentos, Facultad de Veterinaria, Universidad de Zaragoza, Zaragoza, Spain.|Instituto de Biocomputación y Física de Sistemas Complejos (BIFI), BIFI-IQFR (CSIC) Joint Unit, Universidad de Zaragoza, Zaragoza, Spain.
authors.forename: Jorge
authors.initials: J
authors.lastname: Hidalgo
authors.affiliation: Departamento de Producción Animal y Ciencia de los Alimentos, Facultad de Veterinaria, Universidad de Zaragoza, Zaragoza, Spain.|Instituto de Biocomputación y Física de Sistemas Complejos (BIFI), BIFI-IQFR (CSIC) Joint Unit, Universidad de Zaragoza, Zaragoza, Spain.
authors.forename: Pedro
authors.initials: P
authors.lastname: Latorre
authors.affiliation: Instituto de Biocomputación y Física de Sistemas Complejos (BIFI), BIFI-IQFR (CSIC) Joint Unit, Universidad de Zaragoza, Zaragoza, Spain.|Departamento de Bioquímica y Biología Molecular y Celular, Facultad de Ciencias, Universidad de Zaragoza, Zaragoza, Spain.|IIS Aragón, Zaragoza, Spain.
authors.forename: José Alberto
authors.initials: JA
authors.lastname: Carrodeguas
authors.affiliation: Instituto de Biocomputación y Física de Sistemas Complejos (BIFI), BIFI-IQFR (CSIC) Joint Unit, Universidad de Zaragoza, Zaragoza, Spain.|Departamento de Bioquímica y Biología Molecular y Celular, Facultad de Ciencias, Universidad de Zaragoza, Zaragoza, Spain.|IIS Aragón, Zaragoza, Spain.|Fundación ARAID, Government of Aragón, Zaragoza, Spain.
authors.forename: Adrián
authors.initials: A
authors.lastname: Velázquez-Campoy
authors.affiliation: Instituto de Biocomputación y Física de Sistemas Complejos (BIFI), BIFI-IQFR (CSIC) Joint Unit, Universidad de Zaragoza, Zaragoza, Spain.|Departamento de Bioquímica y Biología Molecular y Celular, Facultad de Ciencias, Universidad de Zaragoza, Zaragoza, Spain.|IIS Aragón, Zaragoza, Spain.
authors.forename: Javier
authors.initials: J
authors.lastname: Sancho
authors.affiliation: Departamento de Producción Animal y Ciencia de los Alimentos, Facultad de Veterinaria, Universidad de Zaragoza, Zaragoza, Spain.|Instituto de Biocomputación y Física de Sistemas Complejos (BIFI), BIFI-IQFR (CSIC) Joint Unit, Universidad de Zaragoza, Zaragoza, Spain.
authors.forename: Pascual
authors.initials: P
authors.lastname: López-Buesa
mesh_terms: D000818:Animals; D004791:Enzyme Inhibitors / Q000737:chemistry*; D007527:Isoenzymes / Q000037:antagonists & inhibitors / Q000737:chemistry; D010729:Phosphoenolpyruvate Carboxykinase (GTP) / Q000037:antagonists & inhibitors* / Q000737:chemistry*; D010848:Picolinic Acids / Q000737:chemistry*; D011994:Recombinant Proteins / Q000737:chemistry; D013552:Swine
chemical_list: D004791:Enzyme Inhibitors; D007527:Isoenzymes; D010848:Picolinic Acids; D011994:Recombinant Proteins; C008363:3-mercaptopicolinic acid; D010729:Phosphoenolpyruvate Carboxykinase (GTP)