Effect of pH on the activity of eel esterase towards different substrates

Abstract

Much fundamental information about the structure of the active centre in cholinesterases has been derived from studies on changes of activity with pH. These enzymes show a maximum activity at about pH 7-8. On the acid side, activity falls off in approximately the same manner for all substrates studied. However, in the alkaline range great differences were observed between different esters (Bergmann, Segal, Shimoni & Wurzel, 1956). The bell-shaped form of the pH-activity curves has been interpreted to indicate two different com- ponents of the esteratic site, one of which (the nucleophilic group G1) is inactivated competitively