Phosphoenolpyruvate carboxylase activity from Avena coleoptile tissue. Regulation by H+ and malate

1978 ◽  
Vol 56 (4) ◽  
pp. 404-407 ◽  
Author(s):  
B. C. Hill ◽  
A. W. Bown
Keyword(s):  
Phosphoenolpyruvate Carboxylase ◽  
Enzyme System ◽  
Mass Action ◽  
Direct Inhibition ◽  
Carboxylase Activity ◽  
Pep Carboxylase ◽  
Action Effect ◽  
Avena Coleoptile ◽  
Oxaloacetic Acid ◽  
Regulatory Properties

Preparations of phosphoenolpyruvate (PEP) carboxylase activity from Avenu sativa coleoptile tissue were assayed by measuring the incorporation of labelled bicarbonate into a derivative of oxaloacetic acid or by coupling oxaloacetic acid production to malate dehydrogenase activity and the oxidation of NADH. Malate inhibition of PEP carboxylase activity was found to be noncompetitive, was not due to a mass action effect on the coupled enzyme system or to chelation of Mg2+, and probably involved direct inhibition of the enzyme by malate. Maximal PEP carboxylase activity was exhibited around pH 8.0 and increased 125% between pH 7.0 and pH 7.6. Inhibition by 4 mML-malate was virtually complete at pH 7.0 and decreased to 10% inhibition at pH 8. This information is discussed in the light of data which demonstrates that in response to IAA. coleoptile tissue accumulates malate and secretes H+. The regulatory properties of PEP carboxylase are consistent with a role in malate production which could resist increases in intracellular pH resulting from an auxin-stimulated H+ efflux.

CARBON DIOXIDE FIXATION AND PHOSPHOENOLPYRUVATE CARBOXYLASE IN FERROBACILLUS FERROOXIDANS

1967 ◽  
Vol 13 (11) ◽  
pp. 1413-1419 ◽  
Author(s):  
George A. Din ◽  
Isamu Suzuki ◽  
Howard Lees
Keyword(s):  
Carbon Dioxide ◽  
Phosphoenolpyruvate Carboxylase ◽  
Metabolic Regulation ◽  
Carbon Dioxide Fixation ◽  
Acidic Ph ◽  
Ph Optimum ◽  
Carboxylase Activity ◽  
Intact Cells ◽  
Pep Carboxylase

Carbon dioxide fixation was studied in intact cells and cell-free extracts of Ferrobacillus ferrooxidans. The major pathways of fixation were found to be the carboxydismutase system and the phosphoenolpyruvate (PEP) carboxylase system. PEP carboxylase activity was shown to be under metabolic regulation, similar to the regulation established in heterotrophic microorganisms.Acetyl-CoA stimulated PEP carboxylase activity, while aspartate was inhibitory. The F. ferrooxidans enzyme appeared to have a neutral or acidic pH optimum, in contrast to the same enzyme isolated from heterotrophs.

Phosphoenolpyruvate carboxylase activity in ear organs is related to protein concentration in grains of winter wheat

2008 ◽  
Vol 47 (2) ◽  
pp. 386-391 ◽  
Author(s):  
Y.H. Zhang ◽  
Z.M. Wang ◽  
Q. Huang ◽  
W. Shu
Keyword(s):  
Winter Wheat ◽  
Phosphoenolpyruvate Carboxylase ◽  
Protein Concentration ◽  
Carboxylase Activity

scholarly journals Reclamation of a Saline-Sodic Soil by Use of Molasses and Distillery Slops

1969 ◽  
Vol 50 (3) ◽  
pp. 209-217
Author(s):  
Raúl Pérez Escolar
Keyword(s):  
Puerto Rico ◽  
Organic Acids ◽  
Clay Soil ◽  
Mass Action ◽  
Soil Reclamation ◽  
Exchangeable Sodium ◽  
Dry Period ◽  
Action Effect ◽  
Saturation Extract ◽  
Heavy Clay

Data are presented on a laboratory study conducted to determine the effects of the use of blackstrap molasses and rum distillery slops on the reclamation of a highly saline-alkali heavy clay soil of southwestern Puerto Rico. The study revealed that even the lowest levels of distillery slops and diluted molasses, around 2.3 acre-inch, were sufficient to lower the conductivity of the soil-saturation extract from 67 mmhos/cm. to less than 3, and the exchangeable sodium percentage from 43 to less than 1 percent. It is believed that most of the Ca and Mg found in leachates of columns treated with the most slops or molasses may be attributed to the production of organic acids during the decomposition of slops and molasses. These organic acids rendered soluble the soil-free CaCO3 and MgCO3, widening the Ca and Mg:Na ratio to substitute the sodium by a mass action effect. Subjecting the soil to a dry period in between, the 6 and 7 acre-feet of water did not alter the movement of water and resulted in a complete soil reclamation.

Reduced Sink Activity in Growing Shoot Tissues of Maize under Salt Stress of the First Phase may be Compensated by Increased PEP-Carboxylase Activity

2016 ◽  
Vol 202 (5) ◽  
pp. 384-393 ◽  
Author(s):  
B. W. Hütsch ◽  
T. Osthushenrich ◽  
F. Faust ◽  
A. Kumar ◽  
S. Schubert
Keyword(s):  
Salt Stress ◽  
Carboxylase Activity ◽  
Pep Carboxylase ◽  
Sink Activity ◽  
Growing Shoot

scholarly journals Relationship between NH+4 Assimilation Rate and in Vivo Phosphoenolpyruvate Carboxylase Activity

1990 ◽  
Vol 94 (1) ◽  
pp. 284-290 ◽  
Author(s):  
Greg C. Vanlerberghe ◽  
Kathryn A. Schuller ◽  
Ronald G. Smith ◽  
Regina Feil ◽  
William C. Plaxton ◽  
...  
Keyword(s):  
Phosphoenolpyruvate Carboxylase ◽  
Assimilation Rate ◽  
Carboxylase Activity

Diurnal changes in the regulatory properties of PEP-carboxylase in Crassulacean Acid Metabolism (CAM)

1981 ◽  
Vol 4 (3) ◽  
pp. 251-256 ◽  
Author(s):  
M. KLUGE ◽  
J. BRULFERT ◽  
O. QUEIROZ
Keyword(s):  
Crassulacean Acid Metabolism ◽  
Acid Metabolism ◽  
Diurnal Changes ◽  
Pep Carboxylase ◽  
Regulatory Properties

Photosynthetic Enzyme Activities in the C3-C4 Intermediate Neurachne minor S. T . Blake (Poaceae)

1986 ◽  
Vol 13 (3) ◽  
pp. 399 ◽  
Author(s):  
PW Hattersley ◽  
NE Stone
Keyword(s):  
Malic Enzyme ◽  
Acid Decarboxylase ◽  
Decarboxylase Activity ◽  
Carboxylase Activity ◽  
Pep Carboxylase ◽  
C3 Plant ◽  
Bisphosphate Carboxylase ◽  
C3 Species ◽  
Species Activity ◽  
Pep Carboxykinase

The activities of eight key photosynthetic enzymes were measured in leaf blade extracts of the C3-C4 intermediate Neurachne minor S. T. Blake, its C3 and C4 relatives, C3-C4 Panicum milioides Nees ex Trin., and controls (all Poaceae). Phosphoenolpyruvate (PEP) carboxylase (PEPC) activity in N. minor (5.46 �mol mg Chl-1 min-1) is higher than previously reported for any other C3-C3 plant, and the ratio of ribulose-1,5-bisphosphate carboxylase activity to PEPC activity is lower than for P. milioides or C3 species. Activity of pyruvate,PI dikinase (up to 0.88 �mol mg Chl-1 min-1) is 3-5 times higher than in P. milioides. Assays of NADP-malic enzyme (NADP-ME), NAD-malic enzyme (NAD-ME) and PEP carboxykinase (PCK) show Paraneurachne muelleri (Hack.) S. T. Blake and Neurachne munroi (F. Muell.) F. Muell., N. minor's two close C4 relatives, to be NADP-ME type, as predicted from leaf anatomy. Aspartate and alanine aminotransferase activities in these species are higher than expected, however. N. minor (C3-C4) exhibits higher C4 acid decarboxylase activity than C3 species or P. milioides, for NADP-ME only (up to 1.07 �mol mg Chl-1 min-1). Our results suggest that N. minor possesses a limited C4 acid cycle, and that it is the most C4-like C3-C4 intermediate grass currently identified, comparable with some of the known C3-C4 Flaveria (Asteraceae) species.

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