Kinetics of activase unfolding/aggregation at elevated temperature. At time zero, purified activase was added to assays at 35°C (○), 40°C (●), 42°C (▵), 45°C (▪), and 48°C (□) in the absence (control) and presence (+ATPγS) of 0.75 mm ATPγS. Light scattering was measured over a 10-min time course.