Proteinase K, DNase and RNase Free[shortdesc]DNase and RNase free Proteinase K is commonly used for protein removal during DNA or RNA purification.[ shortdesc] [els_overview] Proteinase K is a broad spectrum serine protease that is widely used in molecular biology research. One of its key properties is its ability to digest a wide variety of proteins, making it useful for removing unwanted proteins from samples or for preparing protein free DNA or RNA for downstream applications.