Hydrophobic interaction of alcian blue with soluble and erythrocyte membrane proteins

Gian Marco Ghiggeri, Giovanni Candiano, Fabrizio Ginevri, Antonio Mutti, Enrico Bergamaschi, Rossella Alinovi, Pier Giorgio Righetti

Research output: Contribution to journalArticlepeer-review


Alcian Blue (AB), a cationic dye widely employed for monitoring negative surface charge variations on red blood cell (RBC), platelet and glomerular membranes of patients with nephrotic syndromes, was found in fact to aggregate with itself and precipitate in the pH range 7.0-7.8, i.e., at the physiological pH values used for performing the binding assay between the dye and cell surfaces. This aggregation appears to be essentially hydrophobic as it is insensitive to urea but fully prevented in presence of 2% zwitterionic detergent. In addition, AB binds to most RBC membrane proteins solubilized by urea-detergent extraction, again suggesting hydrophobic interaction. AB also interacts with freely soluble proteins such as haemoglobin and myoglobin; such binding is disrupted by ethylurea and/or 2% zwitterionic detergent, typical inhibitors of hydrophobic liaisons. AB also strongly binds to myoglobin with all the negative charges blocked by esterification of the carboxyl groups, again ruling out direct interaction via surface negative charges. It is concluded that AB binding to the RBC surface can hardly monitor variations in surface charge due to sialic acid residues but, at best, variations in surface hydrophobicity.

Original languageEnglish
Pages (from-to)347-357
Number of pages11
JournalJournal of Chromatography A
Issue numberC
Publication statusPublished - Oct 28 1988

ASJC Scopus subject areas

  • Analytical Chemistry
  • Clinical Biochemistry
  • Molecular Medicine


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