PMSF is a small molecule serine protease inhibitor used to prevent unwanted proteolysis. It has a wide variety of applications, including a broad utility for common research techniques such as enzyme-linked immunosorbent assay (ELISA) and Western blot. In this white paper, we look at the challenges for those applying PMSF in the latter setting and how, by producing GMP grade PMSF, Actylis has helped biopharmaceutical manufacturers to meet increasingly rigorous regulatory requirements.