Focusing of Proteins in a Horseshoe Microchannel

2008 ◽  
Author(s):  
Jaesool Shim ◽  
Prashanta Dutta ◽  
Cornelius F. Ivory
Keyword(s):  
Capillary Electrophoresis ◽  
Electric Field ◽  
Isoelectric Focusing ◽  
Ph Gradient ◽  
Complex Geometries ◽  
Electrokinetic Phenomena ◽  
Double Peaks ◽  
Zone Electrophoresis ◽  
Carrier Ampholytes ◽  
Ph Range

Ampholyte based isoelectric focusing (IEF) simulation was conducted to study dispersion of proteins in a horseshoe microchannel. Four model proteins (pls = 6.49, 7.1, 7.93 and 8.6) are focused in a 1 cm long horseshoe channel under an electric field of 300 V/cm. The pH gradient is formed in the presence of 25 biprotic carrier ampholytes (ΔpK = 3.0) within a pH range of 6 to 9. The proteins are focused at 380 sec in a nominal electric field of 300 V/cm. Our numerical results show that the band dispersions of a protein are large during the marching stage, but the dispersions are significantly reduced when the double peaks start to merge. This rearrangement of spreading band is very unique compared to linear electrokinetic phenomena (capillary electrophoresis, zone electrophoresis or electroosmosis) and is independent of channel position and channel shape. Hence, one can perform IEF in complex geometries without incorporating hyperturns.

scholarly journals Isoelectric focusing of human liver alkaline phosphatase

1970 ◽  
Vol 118 (2) ◽  
pp. 299-302 ◽  
Author(s):  
A. L. Latner ◽  
Mary E. Parsons ◽  
A. W. Skillen
Keyword(s):  
Alkaline Phosphatase ◽  
Density Gradient ◽  
Isoelectric Focusing ◽  
Isoelectric Point ◽  
Human Liver ◽  
Sucrose Density Gradient ◽  
Ph Gradient ◽  
Alkaline Phosphatases ◽  
Carrier Ampholytes

1. Isoelectric focusing of human liver alkaline phosphatase in a sucrose density gradient with LKB Ampholine as carrier ampholytes is described. 2. Problems due to the chelating properties of the ampholytes and the pH gradient were examined. 3. A reactivation procedure to counter these effects was devised that can probably be used for other alkaline phosphatases. 4. The isoelectric point of human liver alkaline phosphatase was found to be pH3.9.

Hybrid isoelectric focusing: Adsorption of proteins onto immobilized pH gradient matrices and desorption by carrier ampholytes

1987 ◽  
Vol 8 (1) ◽  
pp. 52-62 ◽  
Author(s):  
Klaus Altland ◽  
Arnold von Eckardstein ◽  
Angelika Banzhoff ◽  
Michael Wagner ◽  
Ute Rossmann ◽  
...  
Keyword(s):  
Isoelectric Focusing ◽  
Ph Gradient ◽  
Carrier Ampholytes ◽  
Hybrid Isoelectric Focusing

Effects of Ampholyte Dissociation Constants on Protein Separation in On-Chip Isoelectric Focusing

2008 ◽  
Vol 8 (7) ◽  
pp. 3719-3728 ◽  
Author(s):  
Jaesool Shim ◽  
Prashanta Dutta ◽  
Cornelius F. Ivory
Keyword(s):  
Electric Field ◽  
Isoelectric Focusing ◽  
Protein Separation ◽  
Dissociation Constants ◽  
Ph Profile ◽  
On Chip ◽  
Ph Range ◽  
Separation Of Proteins ◽  
Ampholyte Dissociation ◽  
Ph Profiles

Numerical simulations are presented for ampholyte-based isoelectric focusing in 2D microgeometries. In this study, model proteins are focused in the presence of 25 biprotic ampholytes under an applied electric field. Each protein is considered as a simple polypeptide having ten charge states, while the biprotic ampholytes are selected to generate a shallow pH range of 6 to 9. Straight and contraction-expansion microchannels are considered here, and a nominal electric field of 300 V/cm is maintained for separation of proteins. Six distinct values of ΔpKs between 1 and 3.5 are investigated for ampholytes to form pH profiles in a 1 cm long microchannel. Simulation results show that relatively larger values of ΔpK (ΔpK > 3 are required to form stepless pH profiles in the system. The peak heights and differential resolutions of focused proteins are much higher for lower values of ΔpK for which a stepped pH profile is evident. For each protein, the time it takes for the two edges of a peak to merge increases linearly with ΔpK, while the focusing time goes up exponentially with increasing ΔpK. Both merging and focusing times of protein are higher for contraction-expansion microchannel than those of straight microchannel. For a particular value of ΔpK, the contracted "Zoom" region of contraction-expansion channel is able to form more tightly focused bands than the expanded region.

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