Abstract: This invention relates to the use of thermophilic proteases in combination with mesophilic enzymes, including such use in improved methods for isolation, purification, diagnostic, analytical and manufacturing techniques. In particular, the uses and methods of the invention will facilitate improved purification, diagnostic, analytical and manufacturing techniques, especially those in the field of molecular biology, by providing means of removing contamination and/or undesired constituents, and/or by simplifying the techniques.