Loading Control Antibodies

By Stewart Newlove, PhD

Loading control antibodies are used to confirm that protein loading is the same across a gel. This is essential in order to determine whether the difference in levels of the protein of interest is due to loading variance or sample-to-sample expression level differences. Expression levels of the loading control should not vary between the different sample types.

Loading controls are usually proteins that are constitutively and stably expressed at high levels in the cell type or sample that you are studying. Housekeeping proteins are often chosen as loading controls, including: GAPDH, beta Tubulin, or beta Actin. It is essential to select a loading control that has a different molecular weight to your protein of interest to ensure that the bands are distinct and expression levels quantifiable.

The table below shows the most common loading controls for each sample type.

* The exact molecular weight may vary between species.