Active Oxygen

From Anvita Health Wiki

Contents 1 Introduction 2 More General Terms 3 Additional Terms 4 References

Introduction

• Molecular oxygen (O2) exists in the ground state as a triplet. Thus although energetically favorable, oxidation of organic compounds is slow in the absence of catalysis because nearly all organic compounds are singlets & the interaction is forbidden.

• 1, 2 & 3 electron reduction products of molecular oxygen ( hydroxyl radical, hydrogen peroxide & superoxide) & their derivatives obtained from binding to organic compounds (peroxides & hydroperoxides) are much more reactive than molecular oxygen (O2) itself.
• Some ROS are also radicals,( hydroxyl radical & superoxide).
• ROS are generated in the electron transport chain in mitochondria as a part of normal metabolism & by other oxidoreductases. NOX1, NOXA1, NOXO1, RAC1 & CYBA form a functional multimeric complex supporting ROS production.
• ROS participate in a variety of biological processes including host defense, hormone biosynthesis, oxygen sensing & signal transduction.
• In susceptible cells, low levels of ROS may lead to apoptosis, but high levels are associated with necrosis.
• To protect cells from physiologic & pathologic oxidative stress, antioxidant systems have evolved to keep ROS from reaching cytotoxic levels.

More General Terms

• biochemistry

Additional Terms

• antioxidant
• oxidative stress

References

- Sedlak TW, Snyder SH. Messenger molecules and cell death: therapeutic implications. JAMA. 2006 Jan 4;295(1):81-9. PMID: [1] active oxygen (reactive oxygen species {ROS})