Fig. 3. H₂O₂ activates endogenous PKC enzyme activity in lenses from the control, but not the PKC knockout mice. The supernatants from whole lens extracts of control and PKC knockout (KO) mice were used to determine PKC enzyme activity and protein levels by western blot. (A) Endogenous PKC was immunoprecipitated using PKC antisera. PKC enzyme activity was measured as described in the Materials and methods. Enzyme activity was expressed as a percentage of untreated specific PKC activity. Untreated specific PKC activity was expressed as 100%. Values are means ± s.e.m. for three independent experiments. The asterisks indicate statistical significance (P0.05). (B) Proteins from the supernatants were resolved by SDS-PAGE and immunoblotted with anti-PKC, Cx50, Cx43, aquaporin 0 (AQP0) and caveolin 1 (Cav-1). Results demonstrate that the knockout is specific for PKC. KO, PKC knockout; PBS, phosphate-buffered saline; IB, immunoblot.