The contribution of proton fluctuation to dielectric relaxation in protein solutions

✍ Scribed by G. P. South; E. H. Grant

• Publisher: Wiley (John Wiley & Sons)
• Year: 1973
• Tongue: English
• Weight: 415 KB
• Volume: 12
• Category: Article
• ISSN: 0006-3525
• DOI: 10.1002/bip.1973.360120902

✦ Synopsis

Abstract

Equations are derived which account for the effect of an applied electric field on the fluctuation of protons associated with a macromolecule. The contribution of this proton polarization to the complex permittivity of the macromolecules is evaluated in terms of its effect on both the dispersion due to proton fluctuation and the dispersion caused by dipolar rotation. An expression for the fluctuation correlation time τ__i__δ is derived in terms of the mean lifetimes of the ionised and unionised state τ0 and τ+. If τ__i__δ is very much less than the dipolar correlation time τ__i__, the fluctuation dispersion will occur at much higher frequencies than the dispersion due to orientation polarization; hence the dispersions will be well separated. If τ__i__δ » τ__i__ the two regions would overlap and would be indistinguishable as separate entities. At present insufficient data are available to test rigorously these conclusions but the potentialities of the theory in relation to small globular proteins is shown.