title: Pyruvate kinase in pig liver mitochondria.
abstract: The existence of the pyruvate kinase (PK) in pig liver mitochondria was shown by monitoring photometrically the PK reaction in solubilised mitochondria with either phosphoenolpyruvate (PEP) or ADP used as a substrate. In distinction with the cytosolic isoenzyme, the mitochondrial PK showed a sigmoidal dependence on either PEP or ADP concentrations. The occurrence of the mitochondrial PK was confirmed by immunological analysis. Titration with digitonin showed that mPK is restricted to the matrix. PEP addition to mitochondria resulted in reduction of the intramitochondrial NAD(P)+ inhibited by either the non-penetrant thiol reagent mersalyl or by arsenite, an inhibitor of the pyruvate dehydrogenase complex. Citrate/oxaloacetate appearance outside mitochondria also occurred as result of PEP addition to PLM. Taken together these findings support a role for PEP itself in triggering fatty acid synthesis via its mitochondrial metabolism.
authors.affiliation: Dipartimento di Scienze per la Salute, Università del Molise, via De Sanctis-86100 Campobasso, Italy.
authors.forename: Roberto
authors.initials: R
authors.lastname: Pizzuto
authors.forename: Gianluca
authors.initials: G
authors.lastname: Paventi
authors.forename: Anna
authors.initials: A
authors.lastname: Atlante
authors.forename: Salvatore
authors.initials: S
authors.lastname: Passarella
mesh_terms: D000244:Adenosine Diphosphate / Q000378:metabolism; D000818:Animals; D008930:Mitochondria, Liver / Q000201:enzymology*; D010728:Phosphoenolpyruvate / Q000378:metabolism; D011770:Pyruvate Kinase / Q000032:analysis* / Q000378:metabolism*; D013552:Swine / Q000378:metabolism*
chemical_list: D000244:Adenosine Diphosphate; D010728:Phosphoenolpyruvate; D011770:Pyruvate Kinase