Interaction of Synthetic Polymers with Cell Membranes and Model Membrane Systems IV. Pyran Copolymer

Abstract

We have investigated the interaction of pyran copolymer with erythrocyte ghosts, with intact erythrocytes and with liposomes of pure dipalmitoylphosphatidylcholine (DPPC). Particular attention was given to the importance of divalent metals (especially Ca^(2+)) in promoting the association of pyran copolymer with cell and lipid surfaces. High sensitivity differential scanning calorimetry shows: i) The perturbation of erythrocyte ghost structure by pyran copolymer is not reidily 'bashed out" by treatment with fresh buffer, ii) This perturbation is not due simply to sequestration of metal ions, iii) Pyran copolymer reverses at least partially the effects of Ca^(2+) added to erythrocyte ghosts, and iv) Pyran copolymer raises the transition temperature of DPPC liposomes in the presence of 5 mM Ca^(2+), but not in the absence of added Ca^(2+).

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