Digging Out Low-abundance Proteins From Overloaded Sample By Modified Capillary Electrophoresis

Enrichment is usually required for detecting low-abundance components in a protein complex.But the concentrated sample accompanies an overload of high-abundance proteins in the complex,which will ruin the whole separation due to the serious longitudinal dispersion.Here we proposed a strategy to address this problem based on modified capillary electrophoresis.The overloaded sample is firstly stretched into a wider zone in the higher electric field strength.The sample is then fraction-ated into thin pieces via a cutting effect.As a result,baseline separations can be achieved for these thin pieces of sample due to less longitudinal dispersion.In the experiment,in order to make the method not be affected by other factors,the capillary wall must be coated firstly.Coated capillary can avoid the eletroosmosis flow and the sample adsorption,which may lead to poor reproducibility and instability.And compared with the traditional capillary electrophoresis methodThe feasibility of the new approach is confirmed by separating the overloaded mixture of N,N'-diphenylguanidine and N,N'-bis(o-tolyl)guanidine,and compared with the traditional capillary electrophoresis method.Afterwards,the practicability of the new approach is demonstrated in fractionating a low-abundance protein from high-abundance proteins.