ortho-Tyrosine (o-Tyr)

ortho-Tyrosine is a non-proteinogenic amino acid and a structural isomer of the standard amino acid para-tyrosine. It is formed in vivo through the non-enzymatic hydroxylation of phenylalanine by hydroxyl radicals, making it a specific and sensitive biomarker for oxidative stress and protein damage (PubChem CID 439203; PMID: 9165300). Unlike para-tyrosine, which is synthesized enzymatically by phenylalanine hydroxylase, ortho-tyrosine accumulation indicates a state of increased reactive oxygen species (ROS) production. Elevated levels of ortho-tyrosine have been detected in various pathological conditions, including diabetes, atherosclerosis, and chronic kidney disease, where oxidative damage to proteins plays a significant role in disease progression (PMID: 10459507; PMID: 15607314). It is not considered a therapeutic target for drug intervention but rather a diagnostic tool to assess the extent of oxidative modification of proteins. Research focuses on its utility in monitoring the efficacy of antioxidant therapies and understanding the mechanisms of oxidative injury in clinical settings.

Other names

2-Hydroxyphenylalanineo-Tyrosine2-Hydroxy-L-phenylalanine

Not applicable; ortho-tyrosine is a metabolic byproduct and biomarker, not a therapeutic target.