. Author manuscript; available in PMC: 2012 Nov 18.

Published in final edited form as: ACS Chem Biol. 2011 Sep 26;6(11):1257–1264. doi: 10.1021/cb2002544

Table 1.

Hydrolysis rates of S. tropica proteasome complexes for all active substrates^a

Proteasome complex	Hydrolysis rate (nmol hr⁻¹ mg⁻¹)
Proteasome complex	Suc-LLVY-amc	Ac-RLR-amc	Z-VKM-amc
α/β₁	56.0 ± 1.3	93.8 ± 5.0	51.6 ± 2.7
α/β₁ M45F	46.9 ± 10.7	89.4 ± 6.6	53.8 ± 1.9
α/β₁ A49V	Inactive	Inactive	ND^b
α/β ₁ M45F/A49V	Inactive	Inactive	ND^b

α/SalI	3.4 ± 0.2	Inactive	19.4 ± 0.6
α/SalI F45M	33.1 ± 2.5	Inactive	78.4 ± 0.3
α/SalI V49A	Inactive	Inactive	Inactive
α/SalI F45M/V49A	Inactive	Inactive	Inactive

No activity was observed with substrates Z-LLL-amc, MeOSuc-AAPV-amc, Z-LLE-amc, and Suc-APA-amc. Data shown is the mean ± standard deviation, N = 3.

Both α/β ₁ A49V and α/β ₁ M45F/A49V displayed detectable activity toward substrate Z-VKM-amc. However, these complexes were recovered in low yield and were prone to aggregation upon purification, therefore hydrolytic rates were not determined (ND).