Primary amines and alcohols in biomolecules

Primary amines and alcohols in biomolecules refer to fundamental chemical functional groups rather than a specific, discrete therapeutic target. Primary amines (-NH2) are ubiquitous in biological systems, found at the N-terminus of all proteins, within the side chains of lysine residues, and in various neurotransmitters and nucleic acid bases (NCBI PubChem, 2024). Alcohols (-OH), or hydroxyl groups, are equally prevalent, appearing in amino acids like serine, threonine, and tyrosine, as well as in carbohydrates, lipids, and steroids (Lehninger Principles of Biochemistry). These groups are essential for maintaining molecular structure through hydrogen bonding and are often the sites of critical post-translational modifications such as phosphorylation or glycosylation. In a pharmacological context, these functional groups are not typically targeted for selective disease modulation because they are present in nearly every biological molecule, making specific targeting impossible. Instead, they serve as reactive handles for bioconjugation, such as the attachment of polyethylene glycol (PEG) or cytotoxic payloads in antibody-drug conjugates (Alberts et al., Molecular Biology of the Cell). Agents that react non-specifically with these groups, such as alkylating agents or chemical cross-linkers, generally exhibit high levels of toxicity and are used primarily as disinfectants, fixatives, or in highly controlled chemotherapy regimens.

Other names

Amino groupsHydroxyl groupsNucleophilic functional groupsBiomolecular nucleophiles

Drugs or reagents typically interact with these groups through covalent modification, such as acylation of primary amines or phosphorylation/esterification of alcohols, often utilizing the nucleophilic properties of the nitrogen or oxygen lone pairs (Hermanson, Bioconjugate Techniques, 2013).