Enantioterminal

Enantioterminal refers to the two distinct ends of a biological polymer that exhibit opposite properties or functional groups. The term is most commonly applied to proteins and nucleic acids, which are linear macromolecules essential for life.

In proteins, the enantioterminal ends are the amino terminus (N-terminus) and the carboxyl terminus (C-terminus). The N-terminus is characterized by a free amino group (NH2), while the C-terminus has a free carboxyl group (COOH). Protein synthesis begins at the N-terminus and proceeds towards the C-terminus, a directionality that is crucial for proper protein folding and function. The sequence of amino acids, read from N-terminus to C-terminus, defines the primary structure of a protein.

Similarly, nucleic acids such as DNA and RNA also possess enantioterminal ends. For DNA, these are the 5' (five prime) and 3' (three prime) ends. The 5' end typically carries a phosphate group, while the 3' end has a hydroxyl group. DNA replication and transcription occur in a specific direction, from 5' to 3', guided by the enantioterminal polarity. RNA also exhibits this 5' to 3' directionality, which is vital for its role in protein synthesis and other cellular processes. Understanding the enantioterminal nature of these biomolecules is fundamental to comprehending their biological roles and interactions.