Roles of the tyrosine isomers meta-tyrosine and ortho-tyrosine in oxidative stress.

Roles of the tyrosine isomers meta-tyrosine and ortho-tyrosine in oxidative stress.
Ageing Res Rev. 2016 Mar 31;
Authors: Ipson BR, Fisher AL
Abstract
The damage to cellular components by reactive oxygen species, termed oxidative stress, both increases with age and likely contributes to age-related diseases including Alzheimer's disease, atherosclerosis, diabetes, and cataract formation. In the setting of oxidative stress, hydroxyl radicals can oxidize the benzyl ring of the amino acid phenylalanine, which then produces the abnormal tyrosine isomers meta-tyrosine or ortho-tyrosine. While elevations in m-tyrosine and o-tyrosine concentrations have been used as a biological marker of oxidative stress, there is emerging evidence from bacterial, plant, and mammalian studies demonstrating that these isomers, particularly m-tyrosine, directly produce adverse effects to cells and tissues. These new findings suggest that the abnormal tyrosine isomers could in fact represent mediators of the effects of oxidative stress. Consequently the accumulation of m- and o-tyrosine may disrupt cellular homeostasis and contribute to disease pathogenesis, and as result, effective defenses against oxidative stress can encompass not only the elimination of reactive oxygen species but also the metabolism and ultimately the removal of the abnormal tyrosine isomers from the cellular amino acid pool. Future research in this area is needed to clarify the biologic...

Source: Ageing Research Reviews - March 30, 2016 Category: Genetics & Stem Cells Authors: Ipson BR, Fisher AL Tags: Ageing Res Rev Source Type: research