What is the Origin of D-Amino Acid Isomers?

The nomenclature originates from stereochemistry, where D (dextro) and L (levo) historically denote the direction of rotation of plane-polarized light, a concept later standardized to the absolute configuration around the chiral center. Although D-amino acids were once thought to be exclusive to bacteria and lower organisms, they have been identified in certain mammalian neuropeptides and tissues. In drug design, their use is a direct application of biochemical principles to improve pharmacokinetics.

What is the Mechanism of D-Amino Acid Isomers?

The primary functional mechanism of incorporating a D-amino acid isomer into a peptide sequence is to confer resistance to the body's natural proteases and peptidases, which are highly stereospecific for the L-form. This structural modification shields the peptide from rapid enzymatic hydrolysis, thereby increasing its half-life in the systemic circulation and allowing for a more sustained and potent therapeutic effect. Conversely, endogenous D-amino acids may function as signaling molecules, interacting with specialized receptors or enzymes in neuroendocrine pathways.

D-Amino Acid Isomers ∞ Area

D-Amino Acid Isomers

Meaning

D-Amino Acid Isomers are enantiomers, or mirror-image forms, of the standard L-amino acids that typically form the building blocks of endogenous human proteins and peptides. These molecules share the same chemical composition but possess a distinct spatial configuration around the alpha carbon, fundamentally altering their recognition by biological systems. While L-amino acids are predominant in mammalian life, the incorporation of D-isomers into synthetic peptide therapeutics is a pharmacological strategy to enhance stability and bioavailability.