Figure 3.

Effect of pH on PN stability and carbonyl formation in GS in the absence of CO₂. Reaction mixtures (1.0 ml) contained 3 mM PN, 1.0 mg GS, and 0.3 M K-PO₄ buffer at the specified pH values. After 20 min at room temperature, protein carbonyls (circles) and the half-life of PN (triangles) were determined as described in Materials and Methods.