Functional and biochemical characterization of the 20S proteasome in a yeast temperature-sensitive mutant, rpt6-1

Table 2 Chymotrypsin-like activity of the 20S proteasome in the rpt6-1 mutant as a function of temperature shift^a.

Incubation temp.	Chymotrypsin-like activity (nmol/mg/min)		wt/rpt6-1	Chymotrypsin-like activity (nmol/mg/min)		wt/rpt6-1
	SDS (-)			SDS (+)
	wt	rpt6-1		wt	rpt6-1
25°C	0.58 ± 0.02	0.07 ± 0.03	8.0	4.42 ± 0.29	2.63 ± 0.31	1.6
37°C	0.42 ± 0.04	0.51 ± 0.04	0.8	3.33 ± 0.70	3.73 ± 0.22	0.8

^aExponentially-growing cells at 25°C were shifted to 37°C and incubated for 8 h. Activity assays were carried out with the active Q-sepharose fractions from both strains containing equal amounts of proteasome as described in the methods using Suc-LLVY-MCA as a substrate in the presence (0.01%) and absence of SDS. The values are means ± SD of three independent experiments.

ISSN: 1471-2091