NH2, or the amine group, is a functional group in organic chemistry consisting of one nitrogen atom bonded to two hydrogen atoms. It is commonly found in various organic compounds, including amino acids, which are the building blocks of proteins. The presence of the NH2 group can influence the chemical properties and reactivity of these compounds. In biological systems, NH2 groups play a crucial role in the formation of proteins and nucleotides. They participate in hydrogen bonding and can affect the structure and function of molecules. The amine group is also important in the synthesis of pharmaceuticals and other chemical products.