Botulinum Neurotoxin Detection and Differentiation by Mass Spectrometry
Figure 2. Substrate peptide sequences, the botulinum neurotoxin (BoNT) serotype predicted cleavage product sequences, and masses of the substrate and product peptides. Peptides for BoNT-A and -E were derived from the human SNAP (synaptosomal-associated protein)-25 protein. The substrate peptide for BoNT A, 187-SNKTRIDEANQRATKML-203, was modified to biotin(ε)-KG(K189->R and K201->R)GGK-(ε)Biotin. The BoNT-E substrate sequence was also from human SNAP-25 (156–186). Substrate peptides for BoNT-B and -F are from human synaptobrevin 2; the BoNT-B substrate (3) is from 59–93 in the sequence and the BoNT-F substrate is from 35–74.