PROTPURE.ZIP contains the Window version of Protein Purification. The zip file contains the following: PROTEINS.EXE is the main program ELECTRO.EXE handles the electrophoresis simulation MIXEDIT.EXE is a mixture editor so you can create new .PT1 mixture files DEFAULT.PT1 is the default mixture - edit this with MIXEDIT if you want PROTPURE.SIT and PROTPURE.HQX are both archive files containing the following files for the Macintosh: Protein Purification - the main program Mixture Editor - make your own mixtures Default mixture - a twenty-protein mixture Three Proteins - a three-protein mixture PROTPURE.SIT has been produced with Stuffit and PROTPURE.HQX is PROTPURE.SIT after BinHex has worked on it. Try PROTPURE.SIT first and if you have trouble, then download PROTPURE.HQX. The copyright for these probably still rests with Oxford University Press, so it would be best to regard these as evalution copies. Queries to Andrew Booth bmb6agb@leeds.ac.uk