Figure 6
Kinetic analysis of the thermostability of wild-type and mutant EstE1. The enzymes (6.0 μM) of wild-type EstE1 (●), EstE1F276A (■), EstE1F276E (□), EstE1V274A (▲), EstE1V274A/F276A (▯), EstE1L299D (▼), EstE1R270A (▯), EstE1E295A (▯), and EstE1R270A/E295A (▯), in 20 mM potassium phosphate buffer (pH 7.0) were incubated at 80°C for the indicated times. Residual activities were then determined by measuring the amount of p-nitrophenol released by esterase-catalyzed hydrolysis. The activity of a non-incubated sample was defined as 100%