Seebeck coefficients show " dry " compressed discs of haemoglobin and NaDNA to be p-type, adsorption of water causing a change to n-type behaviour. The magnitude of the effect suggests that simultaneous themodiffusion of adsorbed water may occur so as to magnify the changes in Seebeck coefficient with hydration for haemoglobin.Step function d.c. transients applied to compressed discs of dry haemoglobin reveal two relaxations, designated a for the higher frequencies and for the lower frequencies. The a peak is attributed to a Maxwell-Wagner interfacial polarisation, involving trapping of holes at defects in the compressed discs and the s1 peak to a polarisation at the electrodesemiconductor interface. An alternative explanation relating the a peak to dipolar orientation is also considered.The possibility is discussed that the charge carriers are electrons and holes arising from a charge transfer within the protein, as earlier postulated for NaDNA.
Charge carrier generation and transport in the mitochondrial lipoprotein system has been investigated by electrical conductivity, low frequency dielectric relaxation, and thermoelectric power. A parallel study was conducted on morphological/structural changes by DTA and NMR. The results obtained confirm the need to consider concurrently free charge carrier processes and polarization phenomena. All techniques show a "transition" at the same temperature. The steady state conductivity is correlated with main chain segmental reorientations of the phospholipid moiety below the transition and with an interfacial polarization process above it. The Seebeck coefficient provides a useful new aid to characterizing the charge carriers, confirming that they are electronic. The terminal cytochrome oxidase component was investigated separately but it largely reflected ionic impurities characteristic of the isolation process, so that the results were of no intrinsic value.
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