Abstract Oxidative stress is an important chemical factor associated with cellular dysfunction and results from an imbalance between the production of reactive oxygen species and the ability of cells to eliminate them. This condition has increased interest in developing materials capable of mimicking the activity of natural antioxidant enzymes. Nanozymes are emerging materials with enzyme-like catalytic activities, including catalase-, peroxidase-, and superoxide dismutase-like activities. These materials may contribute to reducing the accumulation of reactive species and protecting cellular components from oxidative damage. Their tunable size, composition, and surface properties make them promising candidates for biomedical and pharmaceutical applications. This article discusses the concept of nanozymes and their potential role in controlling oxidative stress, with emphasis on their emerging importance in modern biochemistry and biomedical research. Introduction Biochemical reactions continuously occur inside living cells and are essential for energy production and the maintenance of cellular functions. During these processes, reactive oxygen species (ROS), including hydroxyl radicals, superoxide, and hydrogen peroxide, can be generated. When the production of ROS exceeds the capacity of cellular antioxidant systems to eliminate them, oxidative stress occurs. Cells possess several natural antioxidant defense mechanisms, including enzymes such as superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx). However, pathological and environmental conditions may increase oxidative burden and damage cellular biomolecules. This has encouraged researchers to investigate new materials capable of mimicking the functions of natural antioxidant enzymes. In recent years, nanozymes have emerged as an interdisciplinary research area connecting biochemistry with nanoscience. Nanozymes are nanomaterials that exhibit enzyme-like catalytic activities and whose chemical and surface properties can be modified. From a biological perspective, these properties may allow nanozymes to interact with reactive species and reduce oxidative damage to proteins, lipids, and nucleic acids. Understanding the relationship between nanozyme chemical structure and biological activity may provide opportunities for designing more selective and efficient materials, particularly for applications involving oxidative stress, inflammation, and cellular protection. Therefore, nanozymes represent a promising research direction in modern biochemistry. Conclusion Nanozymes represent an emerging research direction at the interface between biochemistry and nanoscience. Their ability to mimic the catalytic activities of antioxidant enzymes makes them potentially valuable for controlling reactive species and protecting cellular components from oxidative damage. However, further investigations are required to understand their mechanisms of action, stability, toxicity, and interactions with biological systems before extensive biomedical applications can be developed. Advances in nanozyme design and optimization of their chemical properties may lead to new applications in biochemistry and biomedical research Al-Mustaqbal University – The First University in Iraq