Why do I see a doublet when using my total Histone H3 antibody for western blot?

We see this doublet phenomenon often in a number of different cell lines that we test with our Histone H3 antibodies. It does appear to be sample dependent. The doublet may be due to a proteolytic fragment of Histone H3, either a cleavage product of histone H3 at the N-terminus, or a protein degradation fragment. 

Last updated: October 6, 2025