Vitamin B12 plays a key role in DNA stability. Research indicates that vitamin B12 deficiency leads to indirect DNA damage, and vitamin B12 supplementation may reverse this effect. Vitamin B12 acts as a cofactor for enzymes such as methionine synthase and methylmalonyl-CoA mutase, which are involved in DNA methylation and nucleotide synthesis. These processes are essential for DNA replication and transcription, and any impairment can result in genetic instability. In addition, vitamin B12 has antioxidant properties that help protect DNA from damage caused by reactive oxygen species. This protection is achieved by scavenging free radicals and reducing oxidative stress. In addition to their protective functions, cobalamins can also generate DNA-damaging radicals in vitro that can be useful in scientific research. Research is also being conducted on the use of vitamin B12 in medicine as vectors for xenobiotics. In summary, vitamin B12 is an essential micronutrient that plays a vital role in DNA stability. It acts as a cofactor for enzymes involved in the synthesis of nucleotides, has antioxidant properties and has potential value as a generator of DNA-damaging radicals and drug transporters.

中文翻译：

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维生素 B12——多方面的体内功能和体外应用

维生素 B12 在 DNA 稳定性中发挥着关键作用。研究表明，维生素 B12 缺乏会导致间接 DNA 损伤，补充维生素 B12 可能会逆转这种影响。维生素 B12 是蛋氨酸合成酶和甲基丙二酰辅酶 A 变位酶等酶的辅助因子，这些酶参与 DNA 甲基化和核苷酸合成。这些过程对于 DNA 复制和转录至关重要，任何损伤都可能导致遗传不稳定。此外，维生素 B12 具有抗氧化特性，有助于保护 DNA 免受活性氧造成的损伤。这种保护是通过清除自由基和减少氧化应激来实现的。除了其保护功能外，钴胺素还可以在体外产生损伤 DNA 的自由基，这对科学研究很有用。维生素 B12 在医学中作为异生素载体的用途也正在进行研究。总之，维生素 B12 是一种必需的微量营养素，在 DNA 稳定性中发挥着至关重要的作用。它作为参与核苷酸合成的酶的辅助因子，具有抗氧化特性，并具有作为 DNA 损伤自由基和药物转运蛋白产生剂的潜在价值。