2001 Volume 69 Issue 12 Pages 994-996
Double layer capacitance (Cdl) measurements have been used for in situ monitoring of phospholipase C (PLC) activity at phospholipid monolayers formed on Au(111) electrodes. The enzymatic hydrolysis of the phospholipid monolayer formed on a 1-hexanethiol self-assembled monolayer can be monitored as increase of Cdl of the electrode/solution interface. On the other hand, Cdl of Au(111) modified with 12-bis(11-mercaptoundecanoyl)-sn-glycero-3-phosphocholine monolayer is constant with time in the presence of PLC, indicating that PLC is not active for the monolayer. The difference in the PLC activity between the two systems suggests that flexibility of the lipid molecules at the surface is important for the enzymatic hydrolysis.