Rabbit Anti-Myosin pS19/sP20 Antibody was tested by ELISA, immunohistochemistry and western blotting. Immunoblotting was used to show reactivity with unstimulated and stimulated cardiac myocytes, 3T3 whole cell lysates, and regulatory light chain and smooth muscle phospho recombinant protein. The antibody was also reactive with the phosphorylated form of the immunizing peptide and minimally reactive with the non-phosphorylated form of the immunizing peptide. Although not tested, this antibody is likely functional by immunoprecipitation.