Multiple sites on SARS-CoV-2 spike protein are susceptible to proteolysis by cathepsins B, K, L, S and V

Bioinformatic analysis using PACMANS system identified cleavage sites within SARS-CoV-2 spike protein recognized by furin, cathepsin B, K, L ,S and V. The cleavage of recombinant spike protein by these cathepsins was examined, and several degraded products were observed during each cathepsin digestion. Amino acid sequence analysis suggested that other unknown proteases may be also involved in the cleavage of SARS-CoV-2 spike protein, some of which are considered to be active in an inflammatory events.