Figure 3.

Meta-analysis of data testing the reaction-diffusion thermodynamic (RDT) hypothesis, based on qualitative predictions derived from Equations (11) and (13) (Fig. 2D). (A) Theoretical limits to reaction favorability, ln(K_eq), and enzyme efficiency ln(K_cat/K_m) to achieve T_opt ranging from 0 °C (Cold Limit) to 100 °C (Hot Limit), under reported diffusivity and enzyme concentrations^1,2,37. Data points are for enzymes from mesophile (blue, N = 54) and thermophile (red, N = 28) Prokaryotes and from Eukaryotes (open circles, N = 31). (B) Arrhenius regressions (see Supplementary Information for equations) of reaction favorability, ln (K_eq) versus 1/RT_opt (°K) for Prokaryote and Eukaryote (combined) non-thermophile enzymes, blue, N = 85, R² = 0.31, P < 0.001) and thermophile enzymes (red, N = 28, R² = 0.16, P = 0.032). (C) Regressions of ln (K_cat), for combined non-thermophile (blue, N = 78, R² = 0.11, P = 0.005) and thermophile enzymes (red, N = 28, R² = 0.13, P = 0.06). (D) Regression of change in T_opt, ΔT_opt (°C) induced by experimental change in enzyme efficiency (ΔK_cat/K_m) (N = 17, R² = 0.46, P = 0.003). (E) Significant (all P < 0.02) Arrhenius regressions of enzyme concentration, ln(Z), versus 1/RT_opt(°K)) for each of four different hydrolytic enzymes: β-galactosidase (orange circles, N = 13); α-amylase (blue circles, N = 11), β-glucosidase (open squares, N = 11); β-glucuronidase (open circles, N = 9).