Why do I see a doublet with my beta-Actin antibody?

It is not uncommon to see a doublet with our beta-Actin antibodies depending on the samples being tested. It is likely caused either by phosphorylation of beta-Actin on its many phosphorylation sites, resulting in a shift in size, or by cross-reactivity with gamma-Actin (beta-Actin = 375 amino acids, gamma-Actin (cytoplasmic form) = 333 amino acids).

Last updated: October 6, 2025