3D-Projections Δ H
versus Δ S
and T of a 5D hyperbolic paraboloid using experimental T -independent Δ C
values. The function is specific of the protein mutant family Staphylococcal Nuclease at pH 7; the primary data were obtained from ProTherm entry numbers 107-120. (a) and (b): Two relatively narrow and orthogonally oriented wormholes in the central region of the quadric. (c) and (d): The smaller wormhole — also visible in (b) at higher temperatures — hosts the experimental data, cf. yellow dots in (d), from which the function was calculated using equations 8 and 9 where hT = h0 + h1·T + h2·T· lnT and sT = s0 + s1·T + s2·T· lnT [see additional file 2]. The narrowness of such wormholes is characteristic for a ubiquitous compensation of ΔHT against ΔST , as briefly mentioned in the introduction, and suggests why empirically good, albeit statistically questionable, 2D-linear relationships are found in a vast majority of experimental ΔHT vs. ΔST correlations in the literature.