TABLE 2.

Multiple peptide-hydrolyzing activities of the M. thermophila 20S proteasome

Activity	Substrate	Sp acta (nmol/min/mg of protein)
PG	Cbz-LLE-βNa	115.0 ± 2.3
	Ac-YVAD-Amc	2.2 ± 0.5
	AE-Amc	UDb
CL	Suc-LLVY-Amc	83.7 ± 1.2
	Suc-AAF-Amc	43.7 ± 1.5
	Suc-IIW-Amc	2.4 ± 0.7
	Suc-LY-Amc	UD
	GPL-βNa	UD
TL	Benz-FVR-Amc	2.5 ± 0.4
	Boc-FSR-Amc	1.5 ± 0.3
	GGR-Amc	UD
SNAAP	GG-βNa	UD
	Suc-IA-Amc	UD

^aThe 20S proteasome was heterologously produced in E. coli. The assay mixtures contained 150 μM substrate and 0.027 mg of protein per ml. The reaction temperature was 60°C. 

^bUD, undetectable.