Wagner AP, Psarrou E, Wagner LP. Electrophoretic concentration of proteins in a nonlinear pH gradient.
Anal Biochem 1984;
137:248-55. [PMID:
6731803 DOI:
10.1016/0003-2697(84)90378-6]
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Abstract
A method for electrophoretic concentration of differently charged proteins is described. A nonlinear pH gradient is generated by imposing a potential gradient on an electrolyte system composed of (+)H3PO4-valine (pI 6.0)-Servalyte (pH 9-11)-triethylamine(-). Proteins contained in the valine solution accumulate at the interphase formed between the valine solution and the Servalyte solution. This interphase acts as a barrier or liquid membrane to all proteins having isoelectric points in the range 6-9. For proteins having isoelectric points in the range 5-7 valine is replaced by histidine (pI 7.64) and the Servalyte by Pharmalyte, pH 2.5-5.0. Ribonuclease, hexokinase, bovine serum albumin, and hemoglobin were concentrated and recovered from the top of the column using a peristaltic pump. The duration of concentration process was 1-4 h, the length of the run depending on the experiment scale (20 or 100 ml protein solution), the amount of protein, and the isoelectric point of the protein. Proteins were concentrated 9- to 48-fold, depending on the initial volume and concentration of the protein. The recoveries ranged from 79.7 +/- 1.1 for hemoglobin to 93.17 +/- 2.84 for ribonuclease.
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