Kinetic Silver Staining of Proteins Adsorbed to Microtiter Plates

Abstract

The quantification of proteins adsorbed on microtiter plates is useful for quantitative ELISA and protein interaction assays. One nonradioactive procedure, copper iodide staining, has been described (1 and see Chapter 8). A kinetic silver staining method for measuring the amount of adsorbed protein in a microtiter plate has been developed. This assay has a sensitivity similar to copper iodide staining (5–150 ng/well), but much higher precision (<5%; 2). The kinetic silver staining assay uses the silver staining reagent developed originally by Gottlieb and Chavko for nucleic acids in agarose gels (3). Quantification is based on the time required for staining to reach a fixed optical density. This time-based assay has very little protein-to-protein variation, but is sensitive to interfering substances (2).