FITC-β-Ala-Amyloid β-Protein (1-42) (ammonium) is a fluorescein isothiocyanate (FITC)-tagged monomeric peptide of amyloid beta 1-42, which plays a critical role in the pathogenesis of Alzheimer’s disease, making FITC-β-Ala-Amyloid β-Protein (1-42) (ammonium) a valuable tool for mechanistic studies, drug screening, and biomolecular investigations related to neurodegenerative processes.

β‑Amyloid aggregation protocol (recommended procedure, adjust according to downstream applications).
Monomer preparation:
1. Dissolve solid Aβpeptide in ice‑cold hexafluoro‑2‑propanol (HFIP). Incubate the peptide solution at room temperature (RT)for at least 1 h to ensure complete monomerization and conformational randomization.
2. Obliterate HFIP under vacuum. Store the resulting peptide film at −20 °Cor −80 °C.
Oligomer preparation:
3. Add anhydrous DMSO to the peptide film to prepare a 5 mM stock solution; mix thoroughly by vortexing. Dilute to the desired concentration with ice‑cold PBS or serum‑free, phenol‑red‑free DMEM/F12.
4. Incubate the diluted solution at 4–8 °Cfor 24–48 h. Then centrifuge at 4–8 °C and 14,000 × g for 10 min; soluble oligomers are in the supernatant. Dilute the supernatant 10–200×immediately before use.
Fibril preparation:
5. Add anhydrous DMSO to the peptide film to prepare a 5 mM stock solution; vortex to mix. Dilute to the required concentration with 10 mM HCl.
6. Incubate the diluted solution at 37 °Cfor 24–48 h to obtain Aβ42 fibrils.
Notes:
If insoluble material is present after step 1, extend HFIP treatment (e.g., overnight incubation), vortex, or apply brief sonication; if residues persist, remove by centrifugation or filtration.
Different aggregated forms of Aβ are solution‑labile; prepare fresh whenever possible. For longer‑term storage, keep the peptide as a film at −20 °C or −80 °C.