Merck, 16-663, Magna ChIP® Protein A+G Magnetic Beads

Chromatin immunoprecipitation (ChIP) has been widely adapted for the study of gene-specific and genome-wide distribution of specific DNA and RNA-binding proteins or protein modifications. Similar to standard protein immunoprecipitation assays, ChIP involves isolation of immunocomplexes using a solid medium, such as agarose or magnetic beads, coupled to either IgG binding recombinant protein A or protein G. Experiments comparing protein A vs. protein G vs. protein A/G magnetic bead blends revealed that a mixture of protein A and G beads worked well with a wide variety of antibody isotypes. The use of Protein A/G bead blends eliminated the need to consider which beads or kit to use in order match a particular antibody/bead binding affinity combination. In addition to simplifying the procedure, comparing the use of either protein A or protein G alone, protein A/G magnetic bead blends improved signal-to-noise ratios without decreasing the recovery of input chromatin in ChIP assays.