Effect of cultivation medium on activity, phosphorylation level
and kinetic parameters of phosphoenolpyruvate carboxylase

a 2009

Effect of cultivation medium on activity, phosphorylation level and kinetic parameters of phosphoenolpyruvate carboxylase

DOUBNEROVA, V, K MULLER, Martin ČERNÝ, P SPOUSTOVÁ, H SYNKOVA et. al.

Základní údaje

Originální název

Effect of cultivation medium on activity, phosphorylation level and kinetic parameters of phosphoenolpyruvate carboxylase

Autoři

DOUBNEROVA, V, K MULLER, Martin ČERNÝ, P SPOUSTOVÁ, H SYNKOVA a H RYSLAVA

Vydání

2009

Další údaje

Typ výsledku

Konferenční abstrakt

Utajení

není předmětem státního či obchodního tajemství

Impakt faktor

Impact factor: 3.042

Organizační jednotka

Přírodovědecká fakulta

ISSN

UT WoS

000267069900690

Příznaky

Mezinárodní význam

Změněno: 1. 10. 2010 09:49, doc. Mgr. Martin Černý, Ph.D.

Anotace

V originále

Phosphoenolpyruvate carboxylase (PEPC; E. C. 4.1.1.31) catalyzes the irreversible b-carboxylation of PEP to yield oxaloacetate and inorganic phosphate with participation of HCO3 - ion and divalent metal ion. PEPC is a highly regulated cytosolic enzyme. The phosphorylation status is one of the most important regulatory mechanisms of PEPC. We examined the effect of carbon source (CO2, saccharose in in vitro cultivation medium) on activity and phosphorylation status of PEPC in tobacco plants (Nicotiana tabacum L.). Kinetic parameters such as Michaelis constant, maximal reaction rate, effects of D-glucose-6-P and Lmalate on enzyme activity for phosphorylated and dephosphorylated forms of PEPC were determined. The dephosphorylated form of tobacco PEPC had lower maximal reaction rate, it was less activated by D-glucose-6-P, especially at subsaturation PEP concentrations, but the sensitivity to L-malate was not influenced by phosphorylation. These characteristics of tobacco leaf PEPC were compared with those of PEPC from maize seeds (Zea mays, C4 plant). The dephosphorylation of PEPC from seeds caused the decrease of maximal reaction rate and it changed the kinetics from hyperbolic to sigmoidal one. Unlike to PEPC from tobacco leaves, dephosphorylated form of PEPC from maize seeds was more sensitive to inhibition by L-malate than phosphorylated one. Our results proved that the PEPC phosphorylation caused changes in enzyme kinetic characteristics, which was dependent on plant species.

Citovat

DOUBNEROVA, V, K MULLER, Martin ČERNÝ, P SPOUSTOVÁ, H SYNKOVA a H RYSLAVA. Effect of cultivation medium on activity, phosphorylation level and kinetic parameters of phosphoenolpyruvate carboxylase. 2009. ISSN 1742-464X.

@proceedings{900396,
   author = {Doubnerova, V and Muller, K and Černý, Martin and Spoustová, P and Synkova, H and Ryslava, H},
   title = {Effect of cultivation medium on activity, phosphorylation level and kinetic parameters of phosphoenolpyruvate carboxylase},
   year = {2009}
}

TY  - CONF
ID  - 900396
AU  - Doubnerova, V - Muller, K - Černý, Martin - Spoustová, P - Synkova, H - Ryslava, H
PY  - 2009
TI  - Effect of cultivation medium on activity, phosphorylation level and kinetic parameters of phosphoenolpyruvate carboxylase
N2  - Phosphoenolpyruvate carboxylase (PEPC; E. C. 4.1.1.31) catalyzes the irreversible b-carboxylation of PEP to yield oxaloacetate and inorganic phosphate with participation of HCO3 - ion and divalent metal ion. PEPC is a highly regulated cytosolic enzyme. The phosphorylation status is one of the most important regulatory mechanisms of PEPC. We examined the effect of carbon source (CO2, saccharose in in vitro cultivation medium) on activity and phosphorylation status of PEPC in tobacco plants (Nicotiana tabacum L.). Kinetic parameters such as Michaelis constant, maximal reaction rate, effects of D-glucose-6-P and Lmalate on enzyme activity for phosphorylated and dephosphorylated forms of PEPC were determined. The dephosphorylated form of tobacco PEPC had lower maximal reaction rate, it was less activated by D-glucose-6-P, especially at subsaturation PEP concentrations, but the sensitivity to L-malate was not influenced by phosphorylation. These characteristics of tobacco leaf PEPC were compared with those of PEPC from maize seeds (Zea mays, C4 plant). The dephosphorylation of PEPC from seeds caused the decrease of maximal reaction rate and it changed the kinetics from hyperbolic to sigmoidal one. Unlike to PEPC from tobacco leaves, dephosphorylated form of PEPC from maize seeds was more sensitive to inhibition by L-malate than phosphorylated one. Our results proved that the PEPC phosphorylation caused changes in enzyme kinetic characteristics, which was dependent on plant species.
ER  -

DOUBNEROVA, V, K MULLER, Martin ČERNÝ, P SPOUSTOVÁ, H SYNKOVA a H RYSLAVA. \textit{Effect of cultivation medium on activity, phosphorylation level and kinetic parameters of phosphoenolpyruvate carboxylase}. 2009. ISSN~1742-464X.

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