Antioxidant activity and associated structural attributes of Halomicronema phycoerythrin

In the present study, blue light absorbing pigment protein phycoerythrin (PE) is purified up to molecular grade purity from marine Halomicronema sp. R31DM. The purification method is based on the use of non-ionic detergent Triton-X 100 in ammonium sulphate precipitation. The purified PE is characterized for its antioxidant activity in vitro and in vivo. PE is noted to show substantial in vitro antioxidant activity probed by various biochemical assays. The PE moderated rise in the intracellular-ROS (reactive oxygen species) in wild type Caenorhabditis elegans upon heat and oxidative stress. Further, the antioxidant asset of PE is noted an expedient in averting the ROS associated abnormalities, i.e. impaired physiological behaviour (health span) and aging in C. elegans. The structural attributes of PE contributing to its antioxidant virtue are analysed; the presence of ample residues having antioxidant activity and chromophore-PEB in PE are identified as a source of its antioxidant activity. Furthermore, the stability of PE is assessed under three physico-chemical stresses, temperature, pH and oxidative stress.