Počet záznamů: 1

Characterization of phosphoenolpyruvate carboxylase from mature maize seeds: Properties of phosphorylated and dephosphorylated forms

  1. 1.
    0350036 - UEB-Q 2011 RIV FR eng J - Článek v odborném periodiku
    Černý, M. - Doubnerová, V. - Müller, Karel - Ryšlavá, H.
    Characterization of phosphoenolpyruvate carboxylase from mature maize seeds: Properties of phosphorylated and dephosphorylated forms.
    Biochimie. Roč. 92, č. 10 (2010), s. 1362-1370 ISSN 0300-9084
    Grant CEP: GA MŠk 1M0505
    Výzkumný záměr: CEZ:AV0Z50380511
    Klíčová slova: Phosphoenolpyruvate carboxylase * Phosphorylation * Seed
    Kód oboru RIV: EI - Biotechnologie a bionika
    Impakt faktor: 3.787, rok: 2010

    Phosphoenolpyruvate carboxylase (PEPC, EC 4.1.1.31) from mature maize seeds (Zea mays L.) was purified to homogeneity and a final specific activity of 13.3 mmol min-1 mg-1. Purified PEPC was treated with phosphatase from bovine intestinal mucosa or protein kinase A to study its apparent phosphorylation level. Kinetic parameters of the enzyme reaction catalyzed by phosphorylated and dephosphorylated forms under different conditions were compared, as well as an effect of modulators. The enzyme dephosphorylation resulted in the change of hyperbolic kinetics to the sigmoidal one (with respect to PEP), following with the decrease of maximal reaction rate and the increase of sensitivity to L-malate inhibition. The hyperbolic kinetics of native PEPC present in dry maize seeds was not changed after the protein kinase A treatment, while it was converted to the sigmoidal one after dephosphorylation. Level of PEPC phosphorylation was not affected during seed imbibition.
    Trvalý link: http://hdl.handle.net/11104/0190137