MOPS buffer, also referred to as 3-(N-Morpholino) propanesulfonic acid or 4-Morpholinepropanesulfonic acid, is a zwitterionic biological buffering reagent used widely in biochemical and biological studies. One of Good's buffers, MOPS is suitable for a pH range of 6.5 – 7.9. Its pKa value at 20 °C is 7.15. It is often used in research applications such as cell lysis and extraction, protein assays, protein gel electrophoresis, chromatography, and as a cell culture media component. A downside of this buffer would be its inability to bind with most metal ions and hence it is suggested to be used as a noncoordinating buffer in metallic solutions. It is recommended to avoid sterilization of the MOPS buffers by autoclaving as it can cause degradation and instead sterilize by filtration. Refer to the reagent information provided by the supplier for more details.