Illustration from Scientific Research

The naming convention for substrate residues interacting with the caspase active site 175. The substrate residues to the N-terminal side of the cleaved peptide bond are named P1P4, and the ones to the C-terminal side are named P1P4. Several substrate residues interact with proteases with specific interacting pockets, which are named S (subsite) and numbered following the same logic used as the P1P4 and P1P4 in the substrate. Adapted from 90.

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