peptidemodified

Peptide-modified refers to molecules that carry peptide sequences or peptide-derived moieties, either by covalent attachment to another molecule or by chemical alteration of the peptide itself. In practice, peptide modification is used to tailor properties such as targeting, binding specificity, stability, and solubility. The term is commonly applied in biomedicine, materials science, and analytical chemistry to describe systems where peptides play a functional role on a surface, in a drug, or within a biomolecule.

Modification can occur at various stages. Peptides can be modified during synthesis by incorporating nonstandard amino acids or functional groups, or after synthesis through post-translational or chemical conjugation. Typical strategies include terminal modifications (such as N-terminal acetylation or C-terminal amidation), side-chain functionalization (phosphorylation, glycosylation, lipidation), and conjugation with labels, drugs, or polymers. Reactions frequently used to attach peptide moieties include NHS-ester chemistry, click chemistry (such as azide–alkyne cycloaddition), and Michael addition to cysteine residues. Solid-phase peptide synthesis remains a foundational method for producing and modifying peptides, often followed by purification and analytical verification.

Applications of peptide-modified systems are broad. They include targeted drug delivery with peptide ligands, cell-penetrating peptides to enhance intracellular delivery, antimicrobial or immunomodulatory peptides, and the decoration of nanoparticles, surfaces, or scaffolds with bioactive peptides to influence cell adhesion or signaling. Challenges include ensuring homogeneity, controlling immunogenicity, achieving scalable production, and maintaining stability under physiological conditions. Common examples involve RGD motifs for integrin targeting and lipidated peptides for membrane association.