Table 2.

Unique preferred substrates with unnatural amino acids

Based on screening of an unnatural amino acid HyCoSuL library, optimal single substrates were synthesized for caspase-1 and caspase-11. Each substrate was assayed with either caspase-1 or caspase-11. Most synthesized unnatural amino acid substrates were preferred by caspase-1, with only the best caspase-11 substrates demonstrating about equal catalytic rates with caspase-1. The selectivity factor represents the catalytic parameter k_cat/K_m for caspase-1 divided by that for caspase-11. Each experiment was repeated at least three times, and the k_cat/K_m values are presented as an average. Standard deviations were below 15%.