Increased susceptibility to transglutaminase of eye lens proteins exposed to activated oxygen species produced in the glucose-glucose oxidase reaction.

In order to test whether a mild oxidative stress could promote the transglutaminase damaging effect on eye lens proteins, total lens soluble proteins and purified beta L-crystallin have been exposed to H2O2 slowly produced by the glucose-glucose oxidase reaction. Soon after the pretreatment, the substrate capacity of the lens proteins for an exogenous transglutaminase has been evaluated. Exposure to the oxidative stress increased the susceptibility of the lens proteins to transglutaminase. When ferrous ions were added to the preincubation medium, in order to convert the H2O2 into the hydroxyl radical, the increase was more evident.