Formation of water-soluble radiolabeled products in the absence (a) or presence (b) of EGTA. Assays were performed for the indicated times in the absence or presence of 0.5 mmol/L EGTA. In the absence of EGTA, production increased linearly at least fivefold over a 5-minute period, plateauing between 5 and 30 minutes. When EGTA was added to the reactions, recovery of radioactivity dramatically decreased, indicating its Ca²⁺ dependency. Data are the mean ± SD of at least 3 different experiments.