CHEMOMECHANICAL TRANSDUCTION AND THE SECOND LAW OF THERMODYNAMICS

http://www.ncbi.nlm.nih.gov/pmc/arti...00645-0017.pdf
POLYELECTROLYTES AND THEIR BIOLOGICAL INTERACTIONS, A. KATCHALSKY, pp. 13-15: "Let the polymolecule be a negatively charged polyacid in a stretched state and have a length L. Now let us add to the molecule a mineral acid to provide hydrogen ions to combine with the ionized carboxylate groups and transform them into undissociated carboxylic groups according to the reaction RCOO- + H+ = RCOOH. By means of this reaction, the electrostatic repulsion which kept the macromolecule in a highly stretched state vanishes and instead the Brownian motion and intramolecular attraction cause a coiling up of the polymeric chains. Upon coiling, the polymolecule contracts and lifts the attached weight through a distance deltaL. On lifting the weight, mechanical work f*deltaL was performed... (...) FIGURE 4: Polyacid gel in sodium hydroxide solution: expanded. Polyacid gel in acid solution: contracted; weight is lifted."

https://data.epo.org/publication-ser...9&iepatch=.pdf
Dan Urry, p. 14: "When the pH is lowered (that is, on raising the chemical potential, mu, of the protons present) at the isothermal condition of 37°C, these matrices can exert forces, f, sufficient to lift weights that are a thousand times their dry weight. This is chemomechanical transduction..."

It can rigorously be proved that the chemomechanical transduction described by Katchalsky and Urry does violate the second law of thermodynamics but even a cursory glance would suggest that anti-second-law behaviour is very likely. The work-producing force of contraction increases as hydrogen ions chemically react with the contractile macromolecule but the chemical reaction is spontaneous and, per se, does not consume work. (In a rigorous treatment, the work involved in adding and removing the mineral acid has to be evaluated).

Pentcho Valev