Table 1.

The catalytic parameters in the absence of IDE at pH 7.8 and 37 °C of the chymotrypsin-like activity (employing the fluorogenic LLVY-amc substrate) for h20S, the wt y20S proteasome and its mutant α-3ΔN

	Human	Yeast	α-3ΔN
Chymotrypsin-like kcat (s−1)	12.0 ± 2.7	0.95 ± 0.13	49.6 ± 6.2
Km (M)	1.8 (± 0.3) × 10−3	1.2 (± 0.3) × 10−4	4.1 (± 0.5) × 10−3
Trypsin-like kcat (s−1)	2.0 ± 0.3
Km (M)	5.3 (± 0.7) × 10−5
Caspase-like kcat (s−1)	1.2 ± 0.3
Km (M)	1.1 (± 0.3) × 10−4

For h20S, the catalytic parameters are also reported for the trypsin-like activity (employing the fluorogenic LLR-amc substrate) and for the caspase-like activity (employing the fluorogenic LLE-amc substrate)