Redox properties of tyrosine and related molecules

Redox reactions of tyrosine play key roles in many biological processes, including water oxidation and DNA synthesis. We first review the redox properties of tyrosine (and other phenols) in small molecules and related polypeptides, then report work on (H20)/(Y48)-modified Pseudomonas aeruginosa azurin. The crystal structure of this protein (1.18 angstrom resolution) shows that H20 is strongly hydrogen bonded to Y48 (2.7-2.8 angstrom tyrosine-O to histidine-N distance). A firm conclusion is that proper tuning of the tyrosine potential by a proton-accepting base is critical for biological redox functions. (C) 2011 Federation of European Biochemical Societies. Published by Elsevier B. V. All rights reserved.