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Sample streaks and smears in immobilized pH gradient gels
Author(s) -
EsteveRomero Josep,
SimòAlfonso Ernesto,
Bossi Alessandra,
Bresciani Filippo,
Righetti Pier Giorgio
Publication year - 1996
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.1150170414
Subject(s) - chromatography , sample (material) , chemistry , analytical chemistry (journal)
In immobilized pH gradient (IPG) gel formulations as wide as PH 4–9, encompassing neutrality and containing the p K 7.0 acrylamido buffer as one of the buffering ions, smears are directly proportional to the total amount of the p K 7.0 species. At a total level of 10 m M p K 7.0 in these gel formulations, severe smears occur not only for mildly hydrophobic proteins ( e.g. , recombinant alcalase and termamylase) but also for the relatively hydrophilic p I marker proteins. Streaks and smears are essentially abolished in recipes devoid of the p K 7.0 compound or in formulations containing a maximum of 3 m M of this component. Although partitioning in water/ n ‐octanol has shown the p K 7.0 acrylamido buffer to be quite hydrophobic (P = 0.5), the occurrence of smears could be to the presence of oligomers in some commercial preparations. Even when dissolved in n ‐propanol, some batches of acrylamido buffers might still contain oligomers, probably formed during the synthetic step.