Differences in Cold Inactivation of Phosphoenolpyruvate Carboxylase among C4 Species: The Effect of pH and of Enzyme Concentration

1997 ◽  
Vol 35 (2) ◽  
pp. 169-175 ◽  
Author(s):  
G. Zervoudakis ◽  
K. Angelopoulos ◽  
G. Salahas ◽  
C. D. Georgiou
Keyword(s):  
Phosphoenolpyruvate Carboxylase ◽  
Enzyme Concentration ◽  
Effect Of Ph ◽  
C4 Species ◽  
Cold Inactivation

scholarly journals Species Having C4 Single-Cell-Type Photosynthesis in the Chenopodiaceae Family Evolved a Photosynthetic Phosphoenolpyruvate Carboxylase Like That of Kranz-Type C4 Species

2006 ◽  
Vol 142 (2) ◽  
pp. 673-684 ◽  
Author(s):  
María Valeria Lara ◽  
Simon D.X. Chuong ◽  
Hossein Akhani ◽  
Carlos Santiago Andreo ◽  
Gerald E. Edwards
Keyword(s):  
Single Cell ◽  
Phosphoenolpyruvate Carboxylase ◽  
Cell Type ◽  
C4 Species ◽  
Single Cell Type

Activation and Inactivation of Phosphoenolpyruvate Carboxylase in Leaf Extracts From C4 Species

1978 ◽  
Vol 5 (5) ◽  
pp. 571 ◽  
Author(s):  
MD Hatch ◽  
IR Oliver
Keyword(s):  
Bovine Serum Albumin ◽  
Serum Albumin ◽  
Phosphoenolpyruvate Carboxylase ◽  
Bovine Serum ◽  
Leaf Extracts ◽  
Small Molecular Weight ◽  
Carboxylase Activity ◽  
C4 Species ◽  
The Stability

The stability of phosphoenolpyruvate carboxylase (EC 4.1.1.31) was examined following extraction of the enzyme from leaves of several C4 plants. Extracts were rapidly processed on small Sephadex G-25 columns to free protein of small-molecular-weight compounds. With most of the species examined, activity was rapidly lost at both 0 and 25°C when the pH was about 7.8 or higher. Addition of bovine serum albumin to extracts incubated at 25°C and pH 8.2 not only prevented inactivation with several species, but resulted in a substantial increase in activity. The addition of dithiothreitol plus Mg2+ to extracts from some of these species reduced or prevented inactivation. With extracts maintained at 0°C, addition of either bovine serum albumin or dithiothreitol was effective only in reducing the rate of inactivation in extracts. Phosphoenolpyruvate carboxylase activity remained stable, or increased substantially, when extracts buffered between pH 7.4 and 6.9 were incubated at either 0 or 25°C. Activation was usually complete within an hour and was often significantly greater at 25°C or when bovine serum albumin was added. The activity of partially purified phosphoenolpyruvate carboxylase from Zea mays was similarly affected by pH, temperature, and bovine serum albumin. The present studies raise doubts about the accuracy of phosphoenolpyruvate carboxylase determinations made during the course of some previous studies on C4 species. Reliable procedures for the determination of phosphoenolpyruvate carboxylase activity in C4 plant extracts are described. Possible physiological implications of the results are considered.

The Effect of pH on the Covalent and Metabolic Control of C4 Phosphoenolpyruvate Carboxylase from Sorghum Leaf

1994 ◽  
Vol 315 (2) ◽  
pp. 425-430 ◽  
Author(s):  
C. Echevarria ◽  
V. Pacquit ◽  
N. Bakrim ◽  
L. Osuna ◽  
B. Delgado ◽  
...  
Keyword(s):  
Metabolic Control ◽  
Phosphoenolpyruvate Carboxylase ◽  
Effect Of Ph

scholarly journals Purification of the phosphorylated night form and dephosphorylated day form of phosphoenolpyruvate carboxylase from Bryophyllum fedtschenkoi

1986 ◽  
Vol 239 (1) ◽  
pp. 213-220 ◽  
Author(s):  
G A Nimmo ◽  
H G Nimmo ◽  
I D Hamilton ◽  
C A Fewson ◽  
M B Wilkins
Keyword(s):  
Phosphoenolpyruvate Carboxylase ◽  
Enzyme Concentration ◽  
Amino Acid Sequences ◽  
Major Protein ◽  
Protein Subunit ◽  
Minor Protein ◽  
Low Sensitivity ◽  
A Minor ◽  
Related Amino Acid

Phosphoenolpyruvate carboxylase of Bryophyllum fedtschenkoi was shown to exist in two forms: a night form, which is phosphorylated and has low sensitivity to inhibition by malate, and a day form, which is dephosphorylated and 10 times more sensitive to malate. The day and night forms of the enzyme were purified retaining their distinct malate sensitivities and phosphorylation states. The purified enzymes contained a major protein (subunit Mr 112,000) and a minor protein (subunit Mr 123,000). The two polypeptides appeared to have closely related amino acid sequences and were present in a similar ratio in extracts that had been prepared rapidly. The phosphate present in the night form of the enzyme was covalently bound to serine. It was not a catalytic intermediate. Alkaline phosphatase removed the phosphate group in vitro and increased the malate sensitivity of the enzyme to that observed for the day form. Both the day and night forms of the enzyme were probably tetramers, and their apparent Mr was lowered by the presence of malate, but was unaffected by Mg2+ ions, EDTA, a rise in pH or a 10-fold change in enzyme concentration. The rapid loss of malate sensitivity, observed in extracts of leaves prepared during the day and at night, was shown to be due to proteolysis of the enzyme. It was slowed in the presence of malate and by phosphorylation of the enzyme.

Re-Evaluation of the Effects of Glucose-6-Phosphate and Malate on the Catalytic Properties of Phosphoenolpyruvate Carboxylase From Cynodon dactylon Under Physiological Assay Conditions

1990 ◽  
Vol 17 (4) ◽  
pp. 407 ◽  
Author(s):  
SK Stamatakis ◽  
I Skaliora ◽  
NA Gavalas ◽  
Y Manetas
Keyword(s):  
Phosphoenolpyruvate Carboxylase ◽  
Cynodon Dactylon ◽  
Catalytic Properties ◽  
Enzyme Concentration ◽  
Light Activation ◽  
Apparent Affinity ◽  
Assay Medium ◽  
High Concentrations ◽  
Regulatory Properties ◽  
Assay Conditions

Some catalytic and regulatory properties of the day- and night-form of phosphoenolpyruvate carboxylase (EC 4.1.1.31) from Cynodon dactylon (L.) Pers. leaves were re-evaluated in the presence of high concentrations of glycerol in the assay medium. This cosolute, known to be preferentially excluded from the hydration sphere of some proteins, apparently promotes aggregation, through an increase of the enzyme concentration in a fraction of the total volume. In the presence of this cosolute in the assay medium: (a) glucose-6-phosphate does not activate the enzyme, (b) inhibition of the Vmax by malate is increased, particularly with the night-form of phosphoenolpyruvate carboxylase, whereas the day-form is more responsive at the Km levels, (c) the light activation, detected as an increase in the apparent affinity of the substrate phosphoenolpyruvate is maintained under the new assay conditions.

Light/dark modulation of phosphoenolpyruvate carboxylase in C3 and C4 species

1994 ◽  
Vol 42 (2) ◽  
pp. 133-143 ◽  
Author(s):  
Sanjay K. Gupta ◽  
Maurice S. B. Ku ◽  
Jenq-Horng Lin ◽  
Dianzhong Zhang ◽  
Gerald E. Edwards
Keyword(s):  
Phosphoenolpyruvate Carboxylase ◽  
C3 And C4 Species ◽  
C4 Species
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