%0 Journal Article
%T Characterization of chloroplastic thioredoxin dependent glutathione peroxidase like protein in Euglena gracilis: biochemical and functional perspectives.
%A Raihan MT
%A Tanaka Y
%A Ishikawa T
%J Biosci Biotechnol Biochem
%V 0
%N 0
%D 2024 Jun 26
%M 38925644
%F 2.337
%R 10.1093/bbb/zbae087
%X Euglena gracilis, a fascinating organism in the scientific realm, exhibits characteristics of both animals and plants. It maintains redox homeostasis through a variety of enzymatic and nonenzymatic antioxidant molecules. In contrast to mammals, Euglena possesses non-selenocysteine glutathione peroxidase homologues that regulate its intracellular pools of reactive oxygen species. In the present study, a full-length cDNA of chloroplastic EgGPXL-1 was isolated and subjected to biochemical and functional characterization. Recombinant EgGPXL-1 scavenged H2O2 and t-BOOH utilizing thioredoxin as an electron donor rather than glutathione. Despite its monomeric nature, EgGPXL-1 exhibits allosteric behavior with H2O2 as the electron acceptor and follows typical Michaelis-Menten kinetics with t-BOOH. Suppression of EgGPXL-1 gene expression under normal and high-light conditions did not induce critical situations in E. gracilis, suggesting the involvement of compensatory mechanisms in restoring normal conditions.