TY - JOUR
T1 - Determination of the effective charge of a protein in solution by capillary electrophoresis
AU - Gao, Jinming
AU - Gomez, Frank A.
AU - Härter, Ralph
AU - Whitesides, George M.
PY - 1994/12/6
Y1 - 1994/12/6
N2 - This paper describes two methods to estimate the effective charge of a protein in solution by capillary electrophoresis and demonstrates these methods by using representative proteins. In one method, a 'charge ladder'-a series of derivatives of a protein differing by known increments of charge but differing only minimally in hydrodynamic drag-is generated by covalent modification of the ε-amino groups of lysines with 4-sulfophenyl isothiocyanate or acetic anhydride. In the second method, the equivalent of a charge ladder is produced by noncovalent association of a protein with differently charged ligands. Analysis of the electrophoretic mobilities of the protein and its derivatives as a function of added charge allows the effective charge to be estimated for the unmodified protein. This type of analysis permits estimation of the effective charge of a protein without knowing its composition, structure, or amino acid sequence.
AB - This paper describes two methods to estimate the effective charge of a protein in solution by capillary electrophoresis and demonstrates these methods by using representative proteins. In one method, a 'charge ladder'-a series of derivatives of a protein differing by known increments of charge but differing only minimally in hydrodynamic drag-is generated by covalent modification of the ε-amino groups of lysines with 4-sulfophenyl isothiocyanate or acetic anhydride. In the second method, the equivalent of a charge ladder is produced by noncovalent association of a protein with differently charged ligands. Analysis of the electrophoretic mobilities of the protein and its derivatives as a function of added charge allows the effective charge to be estimated for the unmodified protein. This type of analysis permits estimation of the effective charge of a protein without knowing its composition, structure, or amino acid sequence.
KW - protein charge ladders
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U2 - 10.1073/pnas.91.25.12027
DO - 10.1073/pnas.91.25.12027
M3 - Article
C2 - 7991578
AN - SCOPUS:0028152861
SN - 0027-8424
VL - 91
SP - 12027
EP - 12030
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
IS - 25
ER -