Interaction of polycations with cell-surface negative charges of epithelial cells

A. K. Singh, B. S. Kasinath, E. J. Lewis

Research output: Contribution to journalArticlepeer-review

69 Scopus citations


The interaction between various polycations and cultured glomerular epithelial cells was studied by cell electrophoresis. It was shown that the glomerular epithelial cell presents a negatively charged surface which imparts a zeta potential of -29.0±1.5 mV at the peripheral layer of the plasma membrane. The pH at which the GEC charge became 50% reduced (pKa) was determined to be 3.0. A variety of polycations of various sizes and fixed and flexible geometrics were tested for their capacity to neutralize the cell charge. All the polycations except cytochrome c and lysozyme were capable of completely neutralizing the cell. Cytochrome c could maximally neutralize only 50% of charge and lysozyme only 72% of charge. However, reduced and 'relaxed' molecules of cytochrome c and lysozyme efficiently neutralized the cell surface, as did larger sized 'flexible' polylysines. On the basis of these findings, we conclude that all polycations are not equal in their capacity to neutralize the cell surface. Flexible molecules in contrast to molecules with rigid structures were more effective in neutralizing the cell. This may likely be due to the exposure and availability of more cationic groups in a flexible molecule which results in stabilization of interaction with cells.

Original languageEnglish (US)
Pages (from-to)337-342
Number of pages6
JournalBiochimica et Biophysica Acta (BBA)/Protein Structure and Molecular
Issue number3
StatePublished - Apr 17 1992


  • Glomerular epithelial cell
  • Glomerular filtration unit
  • Polycation

ASJC Scopus subject areas

  • Biophysics
  • Structural Biology
  • Biochemistry
  • Molecular Biology


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