‘Key paper’ for covalent binding of proteins and its uses

A simple method for covalent coupling of proteins to filter paper modified with quinone groups is described. This paper, termed ‘Key paper’ is flexible, stable on storage and does not require any activation before use. Proteins bound to Key paper can be detected by enzyme immunoassay, radioimmunoassay or Coomassie blue staining. Bound enzymes retain their enzymatic activity. Nucleic acids do not bind and do not interfere with the activity of the bound proteins. Because of its mechanical and chemical properties Key paper is a good matrix for electroblotting and for direct in situ analysis of proteins.