Skip to main content
. 2001 Feb 27;98(5):2148–2153. doi: 10.1073/pnas.051515898

Figure 2.

Figure 2

Purified cell-free enzyme catalyzed PO4–H2O oxygen isotope exchange. Positive correlation between δ18O of dissolved inorganic PO4 and water resulting from PO4–H2O exchange catalyzed by hydrolytic phosphoenzymes inorganic pyrophosphatase (PPiase) and alkaline phosphatase (APase). (a) PPiase exchange experiments at 22°C and 30°C in water with δ18O of −19.7‰ to 96.4‰. The initial δ18Op value of dissolved inorganic PO4 before exchange was 13.5‰. (b) APase exchange experiments in −19.4‰ and 44.1‰ water at 37°C using glycero-2-phosphate as an organic-P substrate (P source).