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Negative aurodye for polyacrylamide gels: The impossible stain
Author(s) -
Casero Patriza,
del Campo Gian Battista,
Righetti Pier Giorgio
Publication year - 1985
Publication title -
electrophoresis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.666
H-Index - 158
eISSN - 1522-2683
pISSN - 0173-0835
DOI - 10.1002/elps.1150060803
Subject(s) - chemistry , polyacrylamide , micelle , stain , chromatography , silver stain , polyacrylamide gel electrophoresis , isoelectric focusing , isoelectric point , citric acid , staining , polymer chemistry , aqueous solution , organic chemistry , biology , enzyme , medicine , microbiology and biotechnology , pathology
A negative aurodye for polyacrylamide gels has been developed. After isoelectric focusing in 6 % T polyacrylamide gels, protein fixation and washing, the gel is immersed in 0.01 % HAuCl 4 containing 0.19 % citric acid and 0.1 % Tween 20, freshly made. The free reactants diffuse within the gel fibers and, upon micelle formation, stain the gel matrix purple, leaving white protein zones in sharp contrast. The sensitivity is of the order of 15–20 ng protein/mm 2 , matching and even passing that of silver stain (the lowest detection limit of Coomassie Blue being around 300 ng protein/mm 2 ). The mechanism of background stain does not seem to depend on hydrophobic interaction with the gold‐detergent micelle, as polyacrylamide gelled with hydrophobic cross‐linkers has markedly decreased stain‐binding ability. The formation of mixed micelles of gold with non‐ionic, zwitterionic and anionic detergents has been studied.