Lipid peroxidation product, 4-Hydroxynonenal and its conjugate with GSH are excellent substrates of bovine lens aldose reductase

There is increasing evidence that lipid aldehydes generated endogenously during the process of degradation of lipid peroxides, are causally involved in the pathophysiology effects associated with oxidative stress. We report here that 4-hydroxynonenal (HNE), which is one of the most abundant and toxic lipid aldehyde can be efficiently detoxified by the aldo-keto reductase, aldose reductase, purified from bovine lens. The enzyme displays a K_m of ≃ 9 μM for HNE and 34 μM for the glutathione adduct of HNE (HNE-GS) assigning HNE and HNE-GS to be the best natural substrates of aldose reductase known so far and exposing a new efficient detoxification route of HNE.