Oxidation of tyrosine: Antioxidant mechanism of L-DOPA disclosed

NEYRA RECKY, JAEL R.; SERRANO, MARIANA P; DANTOLA, MARIA LAURA; LORENTE, CAROLINA

FREE RADICAL BIOLOGY AND MEDICINE

ELSEVIER SCIENCE INC

Lugar: Amsterdam; Año: 2021

0891-5849

Tyrosine is an amino acid related to crucial physiological events and its oxidation, that produce beneficial ordetrimental effects on biological systems, has been extensively studied. Degradation of tyrosine often begins withthe loss of an electron in an electron transfer reaction in the presence of a suitable electron acceptor. The reactionis facilitated by excited states of the acceptor in photosensitized processes. Several products of tyrosine oxidationhave been described, the main ones being 3,4-dihydroxy-L-phenylalanine (commonly known as DOPA) andtyrosine dimers. Here, we report tyrosine recovery from tyrosyl radical, after one-electron oxidation, in thepresence of DOPA. We propose that under high oxidative stress the oxidation of tyrosine may be controlled, inpart, by one of its oxidation products. Also, we present strong evidence of antioxidant action of DOPA by preventing tyrosine dimerization, one of the most serious oxidative protein modifications, and the origin of structural modifications leading to the loss of protein functionality.