Enzymes accelerate reactions by lowering activation energy barriers. The standard picture focuses on the active site — the catalytic residues that stabilize transition states, position substrates, and shuttle protons. The rest of the protein provides structural scaffolding but isn't usually credited with active thermodynamic contributions to catalysis.
Mino Galaz et al. (arXiv:2603.20469) measured entropy and information transfer across seven enzymatic systems: TIM-Barrel, human lysozyme, ribonuclease A1, pepsin, β-lactamase, human glucokinase, and carbonic anhydrase II. Across all seven — representing different folds, mechanisms, and functions — they found a directional pattern: entropy and information flow from the peripheral regions of the protein toward the catalytic site.
The periphery isn't passive scaffolding. It's a thermodynamic reservoir that feeds the active site. The distant loops, surface helices, and terminal regions collect conformational entropy from the solvent environment and funnel it inward. The catalytic site doesn't just lower the barrier — it receives the thermodynamic resources to do so from the protein's periphery.
This directional flow across seven unrelated enzyme families suggests a general architectural principle rather than an evolutionary accident. Enzymes are built to concentrate thermodynamic information at the site where chemistry happens, using the rest of the protein as an entropy collection network.
The through-claim: enzyme catalysis is a whole-protein thermodynamic process, not a local chemical one. The active site is where the entropy arrives, not where it originates. The peripheral residues that seem structurally boring are the entropy supply chain.