Figure 2. Enzymatic characterization of CD39L2.

A) pH profile of CD39L2 activity with ADP or ATP at room temperature. CD39L2 has optimal pH at 5.5 and is selectively active on ADP throughout the pH range. B) First-order-rate constant of CD39L2 for ADP or ATP at pH 7.5. The specific rate constant of CD39L2 for ADP or ATP in the kinase assay buffer at room temperature was determined to be 41.0 or 0.7 nmol·min⁻¹ mM⁻¹·µg⁻¹ (the slopes of the curves), respectively. D) Relative CD39L2 activity at different salt concentrations.