Thermal-dependent product specificity over time.

A total of 800 μM 6PG was incubated at different temperatures in 50 mM phosphate solution pH 5 containing 75 μM cysteine and 75 μM FeCl₂, and the formation of different sugar phosphate products was monitored over time. Shown is the cumulative product concentration normalized to the total product quantified at each time by targeted LC/MS. As temperature decreases, the loss of specificity in R5P formation detected at higher temperatures ceases and R5P becomes the predominant sugar phosphate product, also at long term (70% to 80% of total product; blue area). Time ranges are the same as in main Fig 4A and were defined based on the kinetics scaling with temperature. Error bars account for mean ± SD from N = 3 independent experiments (see S1 Data). 6PG, 6-phosphogluconate; LC/MS, liquid chromatography–mass spectrometry; R5P, ribose-5-phosphate.

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