Isoelectric Point

Isoelectric Point

When separating proteins in gel electrophoresis one of the properties used is based on isoelectric point which is called isoelectric focusing (IEF).  This property A gradient of pH is applied to a gel and an electric potential is then applied across the gel which makes one end of the gel more positive than the other.  At all pH’s other than their characteristic isoelectric point, proteins will be charged.  For instance if they are positively charged they will be pulled towards the more negative end of the gel and vise versa. The proteins as such in the first dimension will move along the gel and will accumulate at their isoelectric point.  At this isoelectric point is where the charge of the protein is 0 therefore is now neutral.  Now these proteins can be separated based on a second property in a 2-D gel electrophoresis.

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