Linkers/spacers examples

https://lifetein.com/Peptide_Modifications_Pegylation_Linker.html:

Ahx or b-Ala can be used successfully as spacers during the generation of FITC-labeled peptides, which increases the stability of the fluorescent label. FITC can also be linked easily to a cysteine thiol moiety or to the amino group of lysine at any position. Synthesis using an Ahx linker in the lysine core resulted in better yields. Ahx increases the flexibility of peptide chains, which might help keep peptide chains properly solvated during synthesis, thereby preventing aggregation and increasing the amount of viable growing peptide sequences.