Background: This article describes the effects of nanosecond pulsed electric fields (nsPEFs) on the structure and enzyme activity of three types of proteins. Materials and Methods: Intense (up to 300 kV/cm) 5-ns-long electrical pulses were applied for 500 times at 3 Hz to solutions of lysozyme, albumin, and urease. We analyzed covalent bonds (peptide bonds and disulfide bonds) of lysozyme and albumin, and also the tertiary and quaternary structures of urease as well as urease activity. Results: The results indicated deformation of both the quaternary and tertiary structures of urease upon exposure to an electric field with an amplitude of 250 kV/cm or higher, whereas no structural changes were observed in lysozyme or albumin, even at 300 kV/cm. The enzyme activity of urease also decreased at field strengths of 250 kV/cm or higher. Conclusion: Our experiments demonstrated that intense nsPEFs physically affected the conformation and function of some types of proteins. Such intense electric fields often occur in cell membranes when exposed to a moderate pulsed electric field.
Numerous theoretical studies have been conducted on the effects of high-voltage electric fields on proteins, but few have produced experimental evidence. To acquire experimental data for the amyloid disassemble theory, we exposed transthyretin aggregates to 1 ns 1.26 MV/cm pulsed electric fields (PEFs) to promote transthyretin degradation. The process produced no changes in pH, and the resulting temperature increases were < 1 °C. We conclude that the physical effects of PEFs, rather than thermal or chemical effects, facilitate aggregate degradation.
15Liposomes are widely assumed to present a straightforward physical model of cells. 16However, almost all previous liposome experiments with pulsed electric fields (PEFs) 17 have been conducted in low-conductivity liquids, a condition that differs significantly 18 2 from that of cells in medium. Here, we prepared liposomes consisting of soy bean 19 lecithin and cholesterol, at a molar ratio of 1:1, in higher-conductivity liquid that 20 approximated the conditions of red blood cells in phosphate-buffered saline, with inner 21 and outer liquid conductivities of 0.6 and 1.6 S/m, respectively. We found that a single 22 1.1 kV/cm, 400 s PEF promoted cell-like spontaneous division of liposomes. 23 24
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