Demethylases are enzymes that remove methyl groups from DNA, RNA, or proteins. Methylation is a chemical modification that can influence gene expression and protein function. By reversing this modification, demethylases play a crucial role in regulating various biological processes, including development and cellular differentiation. These enzymes are essential for maintaining proper cellular function and can impact health and disease. For example, abnormal activity of demethylases has been linked to conditions such as cancer and neurodegenerative diseases. Understanding demethylases is important for potential therapeutic approaches in treating these disorders.