Metallothionein is a cysteine-rich protein with a high metal content, widely found in nature. It plays a crucial role in heavy metal detoxification, antioxidant activity, neuroprotection, anticancer effects, and anti-inflammatory functions. Its high sulfhydryl content enables it to effectively scavenge free radicals and mitigate oxidative stress. Metallothionein can also protect normal cells from damage, reduce cancer risk, and alleviate inflammation by scavenging reactive oxygen species. Due to its diverse biological functions, metallothionein has broad applications in environmental protection, disease diagnosis and treatment, and skincare. Metallothionein is classified into various families based on evolutionary relationships, including vertebrate, mollusc, crustacean, prokaryotic, and plant families. Its structure is highly dependent on metal ion binding, with a unique 3D structure containing two domains. Metallothionein's ability to bind metal ions and its antioxidant capacity help reduce damage caused by metal ions and oxidative stress on nerve cells. Metallothionein detoxifies heavy metals by chelating metal ions, reducing their toxicity. It has been shown to detoxify cadmium, zinc, copper, and arsenic. Metallothionein exhibits potent antioxidant properties, effectively scavenging various free radicals, such as hydroxyl and superoxide radicals. Its reaction rate constant with hydroxyl radicals is approximately 300 times higher than that of glutathione. Metallothionein also plays a neuroprotective role by reducing oxidative damage in nerve cells and may be involved in the treatment of diseases such as Alzheimer's and Parkinson's. It has anticancer effects by inhibiting cancer cell growth, migration, and invasion, and promoting apoptosis. Metallothionein also has anti-inflammatory effects by scavenging reactive oxygen species and facilitating tissue repair. Metallothionein has broad applications in environmental protection, disease diagnosis and treatment, and skincare. It can be used as a biomarker for heavy metal pollution, and its expression can be used to assess environmental quality. Metallothionein can be used in the development of products with skincare functions, such as anti-inflammatory, antioxidant, and anti-UV radiation products. Metallothionein can also be used in the diagnosis and prediction of diseases, such as hepatocellular carcinoma, schizophrenia, and Wilson disease. Its expression levels can be used as biomarkers for disease prognosis and treatment. In conclusion, metallothionein has a wide range of biological functions and applications, including heavy metal detoxification, antioxidant activity, neuroprotection, anticancer effects, and anti-inflammatory functions. Its diverse functions make it a promising candidate for use in environmental protection, disease diagnosis and treatment, and skincare. However, the structure of metallothionein varies among different species, and the metal ion binding state in vivo is not fully understood, requiring further research.Metallothionein is a cysteine-rich protein with a high metal content, widely found in nature. It plays a crucial role in heavy metal detoxification, antioxidant activity, neuroprotection, anticancer effects, and anti-inflammatory functions. Its high sulfhydryl content enables it to effectively scavenge free radicals and mitigate oxidative stress. Metallothionein can also protect normal cells from damage, reduce cancer risk, and alleviate inflammation by scavenging reactive oxygen species. Due to its diverse biological functions, metallothionein has broad applications in environmental protection, disease diagnosis and treatment, and skincare. Metallothionein is classified into various families based on evolutionary relationships, including vertebrate, mollusc, crustacean, prokaryotic, and plant families. Its structure is highly dependent on metal ion binding, with a unique 3D structure containing two domains. Metallothionein's ability to bind metal ions and its antioxidant capacity help reduce damage caused by metal ions and oxidative stress on nerve cells. Metallothionein detoxifies heavy metals by chelating metal ions, reducing their toxicity. It has been shown to detoxify cadmium, zinc, copper, and arsenic. Metallothionein exhibits potent antioxidant properties, effectively scavenging various free radicals, such as hydroxyl and superoxide radicals. Its reaction rate constant with hydroxyl radicals is approximately 300 times higher than that of glutathione. Metallothionein also plays a neuroprotective role by reducing oxidative damage in nerve cells and may be involved in the treatment of diseases such as Alzheimer's and Parkinson's. It has anticancer effects by inhibiting cancer cell growth, migration, and invasion, and promoting apoptosis. Metallothionein also has anti-inflammatory effects by scavenging reactive oxygen species and facilitating tissue repair. Metallothionein has broad applications in environmental protection, disease diagnosis and treatment, and skincare. It can be used as a biomarker for heavy metal pollution, and its expression can be used to assess environmental quality. Metallothionein can be used in the development of products with skincare functions, such as anti-inflammatory, antioxidant, and anti-UV radiation products. Metallothionein can also be used in the diagnosis and prediction of diseases, such as hepatocellular carcinoma, schizophrenia, and Wilson disease. Its expression levels can be used as biomarkers for disease prognosis and treatment. In conclusion, metallothionein has a wide range of biological functions and applications, including heavy metal detoxification, antioxidant activity, neuroprotection, anticancer effects, and anti-inflammatory functions. Its diverse functions make it a promising candidate for use in environmental protection, disease diagnosis and treatment, and skincare. However, the structure of metallothionein varies among different species, and the metal ion binding state in vivo is not fully understood, requiring further research.