Immuno slot-blot assay using a membrane which covalently binds protein.

The use of a recently available commercial membrane (Immunodyne Immunoaffinity), which covalently binds proteins, in the development of a quantitative immunological slot blot assay is demonstrated. This membrane was found to be valuable in the quantification of polygalacturonase from tomato fruit, a protein which binds weakly to nitrocellulose membrane. The covalent binding of protein to a solid support allows the use of stringent conditions necessary for reduction of non-specific interactions between antibodies and other proteins. This method should prove useful to develop quantitative immunoassays for proteins which elute from nitrocellulose or other membranes during assay conditions.