Also called D-residue · D-configuration · retro-inverso
Standard amino acids in biology are L-configured (left-handed). D-amino acids are the mirror-image (right-handed) form. Substituting D-residues at vulnerable positions in a peptide resists proteolytic cleavage because enzymes evolved to cut L-peptide bonds cannot recognize the D-chirality. The modification extends half-life at the cost of altered receptor geometry.
Research use only. This definition is an educational reference, not medical advice or dosing guidance.