Electromigration of polyion homopolymers across biomembranes: a biophysical model

The analysis of polyion transmembrane translocation was performed using membrane electrical equivalent circuit. The dependence of polyion flux across membranes on time, membrane electrical conductance, membrane electrical capacitance, degree of polymerization, water solution conductance and applied transmembrane potential is discussed. The changes in polyion flux were up to 88% after 1 ms. Both the increase of polyion chain length and the decrease of membrane conductance resulted in the diminution of this effect. Inversion of flux direction was observed as a result of external potential changes. Reversal curves, representing the values of considered parameters for zero-flux were also shown. The replacement of a polyanion by a polycation of the same chain length resulted in the same shape of the surface plot but with opposite orientation. The analysis describes the effect of transmembrane potential on the translocation rate of polyanionic polysialic acid and polynucleotides, and polycationic peptides across membranes.