ISSN:
1573-6881
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Chemistry and Pharmacology
,
Physics
Notes:
Abstract Solid state electrolysis experiments were performed on the biomolecules, hemoglobin, cytochromec, collagen, lecithin and melanin at various hydration states; and for hemoglobin at various solvation states with methanol adsorbate. The evolved hydrogen was measured and compared with theoretical (Faraday's Law) expectations for the known amount of charge passed through the adsorbents. The difference between the theoretical and actual is a measure of the contributions of electronic charge carriers to the total current. Thus the protonic/electronic conduction ratios are determined. All biomolecules tested appear to be mixed semiconductors. That is, both electronic and protonic charge carriers make significant contributions to the currents over hydration ranges from 6% to above 50%. The constant temperature conductivity increases exponentially with hydration (solvation) but the ratio of protonic to electronic conduction increases linearly with hydration for the globular proteins, hemoglobin and cytochromec. The fibrous protein, collagen, may be a protonic semiconductor in the “dry” state, with an electronic component that increases linearly with hydration. The hemoglobin-methanol system shows only electronic conductivity below 2 BET monolayers, with a sharp onset to 70% protonic conductivity above this value. This result is similar to the DNA-water system previously reported. The protonic/electronic ratio in hydrated hemoglobin may be a function of the applied voltage; being predominantly electronic below 30 volts (300 volts/cm), and a constant mixed value above 100 volts (1000 volts/cm). Our results suggest that both electronic and protonic conduction are intrinsic processes in these substances and subject to control by a number of techniques.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01517187
