Isolating a specific protein from a complex matrix is one of the applications in which our MagSi-protein A or MagSi-protein G beads can be used. The high paramagnetic strength facilitates a quick and easy separation by using a magnet, and the coupled protein A or protein G on the surface makes it possible to bind your own antibody.

As an example, GAPDH (glyceraldehyde-3-phosphate Dehydrogenase) was chosen. GAPDH is one of the so called housekeeping genes and is always expressed in a cell. This protein can be used as a reference when studying the level of protein expression in a cell.

Lane 1 and 2 clearly shows the different subunits of the anti-GAPDH IgG (150 kDa whole molecule, 50 kDa heavy chain and 25 kDa light chain). In-between the heavy and light chain of the IgG, the 37 kDa GAPDH band is visible. The Western blot and chromogenic immunodetection with anti-GAPDH as primary antibody and a POD labelled second antibody confirms this band is GAPDH.