Fig. 1: Multimethod investigation of the enzyme latch theory.

a, The expected relationships proposed by the enzyme latch theory, with relationships labelled (i)–(iv) as in the text. b,c, The matched observed relationships using ‘Traditional’ assay methods (b) versus ‘omics and high-resolution methods (c). In b(i) and c(i), the lower and upper boxplot edges represent the 25th and 75th percentiles, respectively, and the middle line is the median. The whiskers extend from the median to 1.5× the interquartile range. *P = 0.005848, Wilcoxon rank-sum test. In b(ii)–(iv) and c(ii)–(iv), the linear trendlines for significant Pearson correlations (Benjamini–Hochberg P_adj < 0.05) are coloured blue (positive correlation) and red (negative correlation). The shaded regions correspond to the 95% confidence intervals. Water saturation is used as a proxy for oxygen availability, with unsaturated (Unsat.) corresponding to high oxygen, and saturation (Sat.) corresponding to low/no oxygen. Phenol oxidase activity is given by phenol oxidase assay (PO assay, nmol activity g⁻¹ h⁻¹) and the summed metatranscriptome expression of phenol oxidase genes from MAGs in the metatranscriptome (see Methods, PO metaT, geTMM). Polyphenol content is given by Folin–Ciocalteu phenolics (FC polyphenols, mg methyl-gallate equivalents per dry g soil) and polyphenol-like compounds identified in FT-ICRMS (% polyphenols; Supplementary Fig. 11). Extracellular hydrolase enzymes (EHE) are given by beta-glucosidase activity (EHE assay, nmol activity g⁻¹ h⁻¹) and the summed expression of genes encoding glycoside hydrolases from MAGs in the metatranscriptomes (EHE metaT, geTMM). This is representative of relationships observed for other enzyme types (see Supplementary Fig. 3). Porewater CO₂ and CH₄ are given in concentrations (mM). Individual correlation coefficients, P values and sample sizes are given in Supplementary Data 1.