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High performance capillary electrophoresis of calmodulin
Author(s) -
Chan KaiFoon J.,
Chen Wilbur H.
Publication year - 1990
Publication title -
electrophoresis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.666
H-Index - 158
eISSN - 1522-2683
pISSN - 0173-0835
DOI - 10.1002/elps.1150110104
Subject(s) - calmodulin , capillary electrophoresis , electrophoresis , chemistry , chromatography , isoelectric focusing , egta , free flow electrophoresis , gel electrophoresis of proteins , gel electrophoresis , isoelectric point , polyacrylamide gel electrophoresis , biochemistry , calcium , enzyme , organic chemistry
Abstract The electrophoretic properties of purified calmodulin were investigated. High performance capillary electrophoresis of this Ca 2+ ‐binding protein in free solution at pH 2.5 resulted in an elution of a single peak with a retention time of approximately 4.7 min. Addition of [ethylene‐bis(oxyethylenenitrilo)] N, N, N', N' ‐tetraacetic acid (EGTA) to the protein prior to capillary electrophoresis completely abolished this electrophoretic profile. Polyacrylamide gel electrophoresis of calmodulin under denaturing and nondenaturing conditions also revealed a single polypeptide band. However, the relative electrophoretic mobilities of this protein could vary, depending on the presence or absence of Ca 2+ . The p I of calmodulin was estimated to be 3.7 by using isoelectric focusing techniques. Analysis of this acidic protein by high performance capillary electrophoresis at pH 8.0 revealed that it could be resolved into two major and one minor polypeptide peaks, regardless of the presence or absence of Ca 2+ . These findings suggest that capillary electrophoresis at near physiological pH may differentiate the microheterogeneity of calmodulin.