Quantification of redox thermodynamics shifts within coacervates

Area of Science:

• Biochemistry
• Physical Chemistry
• Origin of Life Studies

Background:

• Coacervates are proposed as protoenzymes capable of catalyzing biochemical reactions.
• The thermodynamic mechanisms by which coacervates influence reactions are not fully understood.
• Understanding coacervate microenvironments is crucial for elucidating early life chemistry.

Purpose of the Study:

• To investigate the thermodynamic and kinetic alterations within coacervates.
• To probe the microenvironment of poly-L-lysine and polyuridylic acid coacervates.
• To determine the impact of coacervates on redox reaction thermodynamics.

Main Methods:

• Utilized temperature-dependent electrochemistry to measure reaction entropy, enthalpy, and Gibbs energy.
• Employed the ferri/ferrocyanide redox couple as a probe.
• Performed in situ Raman spectroscopy to analyze coacervate composition.

Main Results:

• Observed an oxidative shift for ferri/ferrocyanide partitioning into coacervates.
• Quantified a 40 J/mol K increase in reaction entropy and an 8 kJ/mol increase in reaction enthalpy.
• Attributed entropy change to a structured water network and enthalpy change to ferrocyanide destabilization.

Conclusions:

• Coacervates significantly alter the thermodynamics of redox reactions.
• The structured water network within coacervates influences entropic contributions.
• Product destabilization within the ionic coacervate phase impacts reaction enthalpy, offering insights into protoenzyme function.