Early stage kinetics of polyelectrolyte complex coacervation monitored through stopped-flow light scattering

Soft Matter ◽  
2016 ◽  
Vol 12 (44) ◽  
pp. 9030-9038 ◽  
Author(s):  
Xiaoqing Liu ◽  
Marie Haddou ◽  
Isabelle Grillo ◽  
Zohra Mana ◽  
Jean-Paul Chapel ◽  
...  
Keyword(s):  
Light Scattering ◽  
Polyelectrolyte Complex ◽  
Early Stage ◽  
Stopped Flow ◽  
Complex Coacervation ◽  
Kinetics Of

scholarly journals Mechanism of Dissociation Kinetics in Polyelectrolyte Complex Micelles

2019 ◽  
Author(s):  
Hao Wu ◽  
Jeffrey Ting ◽  
Matthew Tirrell
Keyword(s):  
Light Scattering ◽  
Polyelectrolyte Complex ◽  
Environmental Changes ◽  
Environmental Parameters ◽  
Underlying Mechanism ◽  
Scattering Data ◽  
Relaxation Rates ◽  
Dissociation Kinetics ◽  
Complex Micelles ◽  
Kinetics Of

<div> <div> <p>Polyelectrolyte-based nanoscale self-assemblies, such as micelles, possess diverse desirable attributes such as capability for sequestering and protecting biomacromolecules against inhospitable environments, responsiveness to external stimuli, and tunability of physical behavior. However, little is known on the mechanisms of dissociation when micelles encounter and respond to environmental changes. Using salt-jump, time-dependent, light scattering, the pathway of dissociation is observed in polyelectrolyte complex micelles that have complex cores and neutral coronas. The micelle dissociation kinetics appear to be a three-staged process, in good agreement with the scattering data. Using kinetic models of amphiphilic block copolymer micelles in polyelectrolyte complexation-driven micelles, we derive an analytical expression for dissociation relaxation rates as a function of solvent temperature, salt concentration, and the length of the charged polymer blocks. The theoretical predictions are compatible with the experimental data from light scattering experiments. This study demonstrates experimentally the relaxation kinetics of polyelectrolyte complex micelle dissociation and illustrates the underlying mechanism governing the dissociation kinetics. It is anticipated that these findings can be generalized to other electrostatic interaction-driven self-assemblies to better understand the relationship among the kinetics of dissociation, constituent polymer properties, and environmental parameters.<br></p> </div> </div>

THE TRYPSIN CATALYZED HYDROLYSIS OF p-NITROPHENYL ACETATE

1959 ◽  
Vol 37 (4) ◽  
pp. 751-759 ◽  
Author(s):  
James A. Stewart ◽  
Ludovic Ouellet
Keyword(s):  
Active Site ◽  
Initial Rate ◽  
Competitive Inhibition ◽  
Early Stage ◽  
Stopped Flow ◽  
Hydrogen Ions ◽  
Experimental Conditions ◽  
Influence Of Ph ◽  
Kinetics Of ◽  
Hydrolysis Of

The hydrolysis of p-nitrophenyl acetate (NPA) by trypsin has been investigated in the early stage of the reaction using stopped-flow techniques. The influence of pH on the initial rate suggests competitive inhibition of the active site of the enzyme by hydrogen ions. The dissociation constant of the enzyme obtained from the kinetics of this reaction (pK = 6.9) indicates possible catalysis by an ammo group or an imidazole group of the enzyme. Lysine methyl ester as an analogue of the enzyme catalyzes the hydrolysis of NPA under similar experimental conditions. The results are described in terms of an assumed mechanism and the nature of the catalytic site is discussed.

pH-Induced Deswelling Kinetics of Sterically Stabilized Poly(2-vinylpyridine) Microgels Probed by Stopped-Flow Light Scattering

Langmuir ◽  
2008 ◽  
Vol 24 (17) ◽  
pp. 9334-9340 ◽  
Author(s):  
Jun Yin ◽  
Damien Dupin ◽  
Junfang Li ◽  
Steven P. Armes ◽  
Shiyong Liu
Keyword(s):  
Light Scattering ◽  
Stopped Flow ◽  
Kinetics Of

Kinetics of ribosome dissociation and subunit association studied in a light-scattering stopped-flow apparatus

Biochemistry ◽  
1976 ◽  
Vol 15 (26) ◽  
pp. 5743-5753 ◽  
Author(s):  
Helmut Goerisch ◽  
Dixie J. Goss ◽  
Lawrence J. Parkhurst
Keyword(s):  
Light Scattering ◽  
Stopped Flow ◽  
Flow Apparatus ◽  
Kinetics Of
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