Although we show that SNO-BACE1 is associated with reduced enzymatic activity, the elevated protein expression and enzymatic activity of BACE1 in late stages of AD may reflect the dominant effect of severe oxidation by H2O2 and peroxynitrite; it has been shown previously that lipid oxidative products, such as 4-HNE, can upregulate BACE1 transcriptionally [30]. This evidence concerns the gene BACE1 and Alzheimer disease.