Comparison of Capsule Resin Data and Kinetic Parameters with Some Static Soil Tests to Predict Potassium Uptake by Rice

2003 ◽  
Vol 34 (15-16) ◽  
pp. 2073-2083 ◽  
Author(s):  
M. Kavoosi ◽  
M. Kalbasi ◽  
A. Aliakbar
Keyword(s):  
Kinetic Parameters ◽  
Potassium Uptake ◽  
Soil Tests

Potassium Uptake by Grass from a Clay and a Silt Soil in Relation to Soil Tests

2001 ◽  
Vol 51 (3) ◽  
pp. 97-105 ◽  
Author(s):  
Anne Falk Øgaard ◽  
Tore Krogstad ◽  
Anne-Kristin Løes
Keyword(s):  
Potassium Uptake ◽  
Soil Tests

Effect of aluminum on potassium uptake by red spruce seedlings

1985 ◽  
Vol 63 (6) ◽  
pp. 1099-1103 ◽  
Author(s):  
J. R. Cumming ◽  
R. T. Eckert ◽  
L. S. Evans
Keyword(s):  
Kinetic Analysis ◽  
Kinetic Parameters ◽  
Nonlinear Least Squares ◽  
Potassium Uptake ◽  
Red Spruce ◽  
Physiological Changes ◽  
Absorption Data ◽  
Aluminum Exposure ◽  
Initial Decrease ◽  
Seedling Roots

Potassium uptake by roots of intact red spruce seedlings exposed to 0, 1, and 4 mg∙L−1 Al3+ was determined using kinetic analysis. Uptake parameters Vmax and Km were estimated by nonlinear least-squares analysis of K+ absorption data fitted to a combined active and linear uptake model. Roots treated with 1 mg∙L−1 Al exhibited enhanced potassium uptake for up to 72 h of aluminum exposure. K+ uptake in the presence of 4 mg∙L−1 Al also increased but was influenced by the duration of exposure to Al in solution. Comparison of kinetic parameters revealed an increase in Vmax in roots treated with aluminum. Km in both 1 and 4 mg∙L−1 aluminum treatments varied consistently with duration of exposure, characterized by an initial decrease in apparent carrier-site affinity followed by Km values trending toward control levels. These changes are hypothesized to result from a combination of physical and physiological changes in red spruce seedling roots induced by Al3+ in solution.

MEASUREMENT OF STEROID BINDING PROTEINS

1970 ◽  
Vol 65 (1_Suppl) ◽  
pp. S104-S121 ◽  
Author(s):  
E. E. Baulieu ◽  
J. P. Raynaud ◽  
E. Milgrom
Keyword(s):  
Kinetic Parameters ◽  
Binding Proteins ◽  
Binding Specificity ◽  
Binding Parameters ◽  
Target Organs ◽  
Biological Mixtures ◽  
Steroid Binding Proteins ◽  
Steroid Binding ◽  
Steroid Binding Protein

ABSTRACT A brief review of the characteristics of steroid binding proteins found in the plasma and in some target organs is presented, followed by some general remarks on binding »specificity« and binding parameters. Useful techniques for measuring binding parameters at equilibrium are reported, both those which keep the equilibrium intact and those which implicate its disruption. A concept is developed according to which the determination of a specific steroid binding protein is based on the »differential dissociation« of the several steroid binding complexes present in most biological mixtures. Methods which allow determination of the kinetic parameters of the binding systems are also presented. Various representations of the binding and therefore different modes of graphic representation and calculation are discussed, including the recent »proportion graph« method.

THE INFLUENCE OF ETHANOL ON THE CONVERSION OF PREGNENOLONE TO PROGESTERONE BY HUMAN PLACENTAL MICROSOMES

1974 ◽  
Vol 76 (1) ◽  
pp. 178-188 ◽  
Author(s):  
H. Lübbert ◽  
K. Pollow ◽  
R. Wagner ◽  
J. Hammerstein
Keyword(s):  
Kinetic Parameters ◽  
Enzyme Preparation ◽  
Ethanol Concentration ◽  
Hydroxysteroid Dehydrogenase ◽  
Product Formation ◽  
Linear Increase ◽  
Maximal Velocity ◽  
Microsomal Enzyme ◽  
Temperature Optima ◽  
Substrate Concentrations

ABSTRACT The effects of ethanol on kinetic parameters of placental Δ5-3β-hydroxysteroid dehydrogenase were studied. In the presence of high pregnenolone concentrations (50 μm, [S] > Km) the microsomal enzyme preparation exhibited an almost linear increase in activity as the ethanol concentration in the medium was raised from 2.5 to 15 % (v/v). At lower substrate concentrations ([S] << Km) ethanol caused inhibition. Other effects of ethanol were: linearity of product formation with time was prolonged; the maximal velocity was markedly increased; the Km for pregnenolone slightly decreased with increasing ethanol concentrations (2.5 to 10 %, v/v) whereas the Km for NAD remained the same. The pH and temperature optima of the reaction were unaffected by ethanol. Other organic solvents caused similar effects.

Evaluation of Kinetic Parameters at the Transport of Indole-3-acetic Acid Through Bulk Liquid Membranes

2017 ◽  
Vol 68 (5) ◽  
pp. 903-907
Author(s):  
Ecaterina Anca Serban ◽  
Ioana Diaconu ◽  
Elena Ruse ◽  
Georgiana Ileana Badea ◽  
Adriana Cuciureanu ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Kinetic Parameters ◽  
Trioctylphosphine Oxide ◽  
Bulk Liquid ◽  
Transport Parameters ◽  
Kinetics Parameters ◽  
First Order ◽  
Phase Concentration ◽  
Feed Phase ◽  
Indole 3 Acetic Acid

Indole-3-acetic acid is a growth phytohormone considered the most important representative of auxin class. This paper presents the assessment of some kinetic parameters in the process of transport of indole-3-acetic acid taking into consideration the kinetic model of consecutive irreversible first order reactions. It was pursued the influence upon the process of parameters such as: feed phase concentration, stripping phase concentration in the presence of two type carriers: tributyl phosphate (TBP) and trioctylphosphine oxide (TOPO). Depending on these transport parameters were calculated kinetics parameters such as: pseudo-first-order apparent membrane entrance and exit rate constants, the maximum flux at the entrance and exit out of the membrane. The highest values of the transport flux is obtained in the presence of carrier trioctylphosphine oxide (TOPO) at the concentration in the feed phase of 10-4 mol/L indole-3-acetic acid and a concentration of 10--2mol/L NaOH in the stripping phase.

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