![]() ![]() New Phytologist © 2018 New Phytologist Trust. These H 2 O 2 sensors, combined with the detection of specific proteins modified by H 2 O 2, will allow a deeper understanding of its signalling roles.Īscorbate peroxidase (APX) catalase hydrogen peroxide (H2O2) oxidative stress peroxidase peroxiredoxin reactive oxygen species (ROS) superoxide (O2 Quantification of the sources and sinks of H 2 O 2 is being improved by the spatial and temporal resolution of genetically encoded H 2 O 2 sensors, such as HyPer and roGFP2-Orp1. H 2 O 2 oxidizes specific cysteine residues of target proteins to the sulfenic acid form and, similar to other organisms, this modification could initiate thiol-based redox relays and modify target enzymes, receptor kinases and transcription factors. The role of H 2 O 2 in signalling, for example during acclimation to stress and pathogen defence, has received much attention, but the signal transduction mechanisms are poorly defined. However, hydrogen peroxide can have phytotoxic effects on plants at high concentrations. Recently, hydrogen peroxide products have been used to remove algae from irrigation lines and sanitize hydroponic systems between uses. ![]() Excess H 2 O 2 triggers chloroplast and peroxisome autophagy and programmed cell death. Hydrogen peroxide has been used as a sanitation agent for many years. Apoplastic H 2 O 2 influences cell expansion, development and defence by its involvement in type III peroxidase-mediated polymer cross-linking, lignification and, possibly, cell expansion via H 2 O 2 -derived hydroxyl radicals. Intracellular transport is facilitated by aquaporins and H 2 O 2 is removed by catalase, peroxiredoxin, glutathione peroxidase-like enzymes and ascorbate peroxidase, all of which have cell compartment-specific isoforms. Where next? 1209 Acknowledgements 1209 References 1209 SUMMARY: Hydrogen peroxide (H 2 O 2 ) is produced, via superoxide and superoxide dismutase, by electron transport in chloroplasts and mitochondria, plasma membrane NADPH oxidases, peroxisomal oxidases, type III peroxidases and other apoplastic oxidases. Metabolic functions of H 2 O 2 1207 VIII. ![]() Control of H 2 O 2 concentration: how and where? 1205 VII. Production of H 2 O 2 : enzymes and subcellular locations 1200 V. Measurement and imaging of H 2 O 2 1198 III. ![]()
0 Comments
Leave a Reply. |