Preferential processing of big ET-3 by wild-type s-Kell. Big ET-1, big ET-2, or big ET-3 was incubated for 15 minutes with wild-type s-Kell. As a control, the E582G mutant was also incubated with big ET-3. Endothelins produced were measured by EIA. A legend is included in the top left side of the figure.