On the quantitative Amido Black B staining of protein spots in agar gel at low local protein concentrations

Abstract

Protein spots in agar gel of identical protein content but different in surface area are found to bind different amounts of dye upon staining with Amido Black B. The lower the protein concentration within the agar gel, the more the Amido Black B content of the spot falls short of the value expected from the amount of protein present, as measured by means of its ultraviolet-light absorption.

If, however, pure agarose is used instead of agar, the relationship between the protein and dye contents of spots is linear down to protein concentrations of 0.05 μg per mm2 spot surface.