{'fraction_non_alphanumeric': 0.02973977695167286, 'fraction_numerical': 0.026022304832713755, 'mean_word_length': 5.471153846153846, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Phosphorylation of peroxiredoxin 6 changes its conformation and increases its binding to phospholipids

Peroxiredoxin 6 (Prdx6), a unique non‐seleno mammalian peroxidase, is a bifunctional protein with GSH peroxidase and acidic‐calcium independent phospholipase A2 (aiPLA2) activities. It has been shown previously that phosphorylation of Prdx6 by mitogen activated protein kinase regulates its aiPLA2 activity. This study focused on the equilibrium and kinetic aspects of the interaction of recombinant native and phosphorylated human Prdx6 with liposomes at pH 7.4 using circular dichroism (CD) and fluorescence techniques. Phosphorylation of Prdx6 decreased its negative far‐UV CD peak and tryptophan fluorescence quenching indicating a conformational change of the protein. Using native tryptophan fluorescence emission or fluorescence from DNS‐PE labeled liposomes, Prdx6 bound only to oxidized liposomes (apparent binding constant, K, 30.3 ± 11.1 μM) while phosphorylated Prdx6 bound to both reduced and oxidized liposomes (K= 18.5 ± 5.8 and 32.9 ± 11.8 μM, respectively). These specific interactions were confirmed by analysis of the far‐UV CD spectrum of Prdx6. Our results indicate that change in the conformation of Prdx6 upon its phosphorylation allows binding to its lipid substrate as the basis for enhanced PLA2 activity at pH 7.4.