Instability and non-linearity of the pH gradient formed in isoelectric focusing

1979 ◽  
Vol 174 (1) ◽  
pp. 1-11 ◽  
Author(s):  
A. Murel ◽  
I. Kirjanen ◽  
O. Kirret
Keyword(s):  
Isoelectric Focusing ◽  
Ph Gradient

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.

Differential Radioactive Proteomic Analysis of Microdissected Renal Cell Carcinoma Tissue by 54 cm Isoelectric Focusing in Serial Immobilized pH Gradient Gels

2005 ◽  
Vol 4 (6) ◽  
pp. 2117-2125 ◽  
Author(s):  
Slobodan Poznanović ◽  
Wojciech Wozny ◽  
Gerhard P. Schwall ◽  
Chaturvedula Sastri ◽  
Christian Hunzinger ◽  
...  
Keyword(s):  
Renal Cell Carcinoma ◽  
Cell Carcinoma ◽  
Isoelectric Focusing ◽  
Proteomic Analysis ◽  
Renal Cell ◽  
Ph Gradient ◽  
Carcinoma Tissue ◽  
Renal Cell Carcinoma Tissue

Study on stability mechanism of immobilized pH gradient in isoelectric focusing via the Svensson–Tiselius differential equation and moving reaction boundary

Talanta ◽  
2013 ◽  
Vol 111 ◽  
pp. 20-27 ◽  
Author(s):  
Chen-Gang Guo ◽  
Si Li ◽  
Hou-Yu Wang ◽  
Dong Zhang ◽  
Guo-Qing Li ◽  
...  
Keyword(s):  
Differential Equation ◽  
Isoelectric Focusing ◽  
Ph Gradient

Multistage Isoelectric Focusing: A Novel On-Chip Bio-Separation Technique

2005 ◽  
Author(s):  
Prashanta Dutta ◽  
Keisuke Horiuchi ◽  
Huanchun Cui ◽  
Cornelius F. Ivory
Keyword(s):  
Isoelectric Focusing ◽  
Microfluidic Chip ◽  
Soft Lithography ◽  
Fluorescent Protein ◽  
Ph Gradient ◽  
Resolving Power ◽  
Protein Species ◽  
Second Stage ◽  
On Chip ◽  
Bonding Technique

This experimental study reports a method to increase the resolving power of isoelectric focusing (IEF) on a polymeric microfluidic chip. Microfluidic chip is formed on poly-di-methyl siloxane (PDMS) using soft lithography and multilayer bonding technique. In this novel bioseparation technique, IEF is staged by first focusing protein species in a straight channel using broad-range ampholytes and then refocusing segments of that first channel into secondary channels that branch out from the first one. Experiments demonstrated that three fluorescent protein species within a segment of pH gradient in the first stage were refocused in the second stage with much higher resolution in a shallower pH gradient. A serially performed two-stage IEF was completed in less than 25 minutes under particularly small electric field strength up to 100 V/cm.

Relation of age to isoenzyme pattern and total activity of amylase in serum.

1981 ◽  
Vol 27 (3) ◽  
pp. 451-454 ◽  
Author(s):  
P J Bossuyt ◽  
R Van den Bogaert ◽  
S L Scharpé ◽  
Y Van Maercke
Keyword(s):  
Thin Layer ◽  
Isoelectric Focusing ◽  
Serum Amylase ◽  
Amylase Activity ◽  
Total Activity ◽  
Ph Gradient ◽  
Isoenzyme Pattern ◽  
Isoelectric Points ◽  
Age Dependent ◽  
Gel Isoelectric Focusing

Abstract Pancreatic and salivary isoenzymes of amylase were determined in serum from 70 subjects. Thin-layer gel/isoelectric focusing was used to separate the isoenzymes. Because other studies (J. Lab. Clin. Med. 90: 141-151, 1977) show that the major isoamylases have isoelectric points between 5.8 and 7.2, we focused the sera on polyacrylamide gel plates with a pH gradient from 5.5 to 8.5. The separated amylase fractions were made visible by direct incubation with a commercially available dye-starch polymer. Isoelectric focusing proved to be convenient, precise, and reproducible, and it can be used as a routine analysis to detect even slight changes in serum amylase distributions. We found that the isoamylase distribution is age dependent, whereas total amylase activity shows no correlation with age.

Chromatofocusing and isoelectric focusing in immobilized pH gradients compared for characterization of human hemoglobin variants.

1989 ◽  
Vol 35 (3) ◽  
pp. 425-430 ◽  
Author(s):  
R Paleari ◽  
C Arcelloni ◽  
R Paroni ◽  
I Fermo ◽  
A Mosca
Keyword(s):  
Los Angeles ◽  
Isoelectric Focusing ◽  
Ph Gradient ◽  
Resolving Power ◽  
Human Hemoglobin ◽  
Ph Gradients ◽  
Hemoglobin Variants

Abstract We compared the performance of two highly resolving methods, chromatofocusing (CRF) and isoelectric focusing in immobilized pH gradients (IPGF), for the separation of human hemoglobin variants. Lysates containing 13 different hemoglobins, including variants of clinical and geographical importance, and four electrophoretically "silent" variants (Hb Brockton, Hb Cheverly, Hb Köln, and Hb Waco) were analyzed. Both techniques showed a good intrarun precision (CV = 0.87% for CRF, 0.27% for IPGF) and high and similar resolving power (0.010 pH units, with the pH gradients used in this work). The use of an ultranarrow IPGF range (pH 7.15-7.35; pH gradient = 0.019 pH/cm) allowed the resolution between Hb Brockton, Hb Köln, and Hb A. In some cases (Hb D-Los Angeles, Hb F, Hb Waco), the variants were separated from Hb A in different orders, depending on which technique was used, probably because of the different analytical principles of the two methods. As a second-level test, both procedures are informative for characterization of human hemoglobin variants.

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