Table II.
Hydrolysis of different substrates by purified 20S proteasome
| Substrate | Final Concentration | Specific Activity |
|---|---|---|
| μm | nmol mg−1 h−1 | |
| Suc-LLVY-AMC | 100 | 135 ± 3.5 |
| N-Carbobenzoxy (Cbz)-A-A-P-AMC | 100 | 54 ± 5 |
| Cbz-G-G-R-β-napthylamide (βNA) | 170 | 224 ± 12 |
| Cbz-Leu-Leu-Glu(LLE)-βNA | 170 | 59 ± 2 |
| L-Ala-βNA | 100 | n.d. |
| L-Leu-βNA | 100 | n.d. |
| L-Arg-βNA | 100 | n.d. |
| L-Phe-βNA | 100 | n.d. |
| L-Pro-βNA | 100 | n.d. |
| cpm μg−1 | μg casein mg−1 h−1 | |
| Casein-125I | 2.104 | 359 ± 25 |
Assays were performed as described in “Materials and Methods.” n.d., Not detected.