Entropins

Entropins are a term that appears in a small subset of theoretical discussions in biochemistry and biophysics to describe molecules or molecular motifs proposed to influence the entropy component of biological processes. The term is not established as a formal chemical or protein family, and it is not widely used in mainstream databases or textbooks. When used, entropins are described as peptides or small molecules whose activity is attributed predominantly to changes in configurational or solvent entropy, rather than to enthalpic interactions.

In proposed models, entropins may affect protein folding, binding equilibria, membrane interactions, or signaling pathways by modulating the distribution of molecular states. Hypothesized mechanisms include increasing the conformational entropy of a binding partner, promoting disordered states, or inducing favorable solvent reorganization that contributes to the free energy change via entropy. However, there is no consensus on a precise definition, and the concept is largely speculative.

The scholarly use of entropins is limited, with few peer-reviewed studies providing reproducible experimental evidence. Critics argue that without a clear operational definition and standardized measurement, the term risks conflating established thermodynamic analyses of entropy with an ill-defined class of molecules. As a result, entropins remain a fringe concept rather than a recognized category in molecular science. Researchers typically address entropy changes in biological systems with conventional thermodynamic and calorimetric methods, rather than naming a specific class of entropic agents.