Figure 4.

Respiratory fluxome analysis after ¹³CO₂ labeling and measurement of ¹³C enrichments in C-atom positions in metabolites with ¹³C-NMR on detached X. strumarium leaves. CO₂ labeling was done under 400 μmol mol⁻¹ CO₂, 21% O₂, 400 μmol m⁻² s⁻¹ photosynthetically active radiation, and 21°C. Transmission coefficients of metabolic reactions (F_j values) are indicated in red. The in vitro H/D isotope effects associated with the enzymes of interest are indicated in parentheses. Colored cells indicate the observed H₂O/D₂O effect on the average molecular ¹³C enrichment (cell A) and the metabolite concentration measured with gas chromatography coupled to time-of-flight mass spectrometry (cell B). Asterisks indicate that the isotope effect has not been measured, so assumed values obtained with comparable enzymes are shown. Corresponding references for H/D isotope effects are given in Supplemental Table S1.