Choosing the Right Peptide Modification for Your Study

Detection & imaging: FITC/5-FAM for in vitro (400-600 nm); Cy5.5/ICG for in vivo (650-900 nm, low background).

Affinity purification & ELISA: Biotin with 6-Ahx spacer, or KLH/BSA/OVA carrier conjugation for immunogens.

Stability & half-life: N-terminal acetylation (free), PEGylation, stapling, D-amino acid substitution.

Nuclear imaging precursors: DOTA (68Ga/177Lu), NOTA, HYNIC.

Enzymology: pNA/AMC/AFC chromogenic-fluorogenic substrates, FRET pairs.