Table 2. Degradation of purified variable-tail substrates in vitro.
Fitted parameters from Michaelis-Menten analysis of substrate degradation by ClpXΔNP. No fit – substrate degradation too slow to be accurately fit. Values are the average of three biological replicates ± S.D.
| Substrate | Vmax (min−1 hex−1) | KM (μM) |
|---|---|---|
| Gly12 | No fit | |
| GA | 2.4 ± 0.1 | 1.7 ± 0.1 |
| Titin | 2.3 ± 0.2 | 1.1 ± 0.1 |
| Basic | 1.1 ± 0.1 | 1.4 ± 0.1 |
| Acidic | 2.7 ± 0.3 | 1.9 ± 0.2 |
| Tyr1 | No fit | |
| Tyr2 | 0.10 ± 0.03 | 0.7 ± 0.2 |
| Tyr3 | 0.7 ± 0.2 | 1.3 ± 0.2 |
| Tyr4 | 1.7 ± 0.1 | 1.9 ± 0.2 |
| Tyr5 | 1.1 ± 0.1 | 1.2 ± 0.1 |
| Tyr6 | 0.08 ± 0.02 | 0.7 ± 0.3 |
| Tyr7 | No fit | |
| Tyr8 | No fit | |
| Ala4 | 0.13 ± 0.06 | 1.6 ± 0.8 |
| Arg4 | 0.4 ± 0.1 | 1.8 ± 0.4 |
| Asn4 | No fit | |
| Asp4 | No fit | |
| Cys4 | 0.16 ± 0.04 | 0.9 ± 0.4 |
| Glu4 | 0.11 ± 0.06 | 1.1 ± 0.6 |
| Gln4 | 0.40 ± 0.07 | 1.8 ± 0.3 |
| Ile4 | 1.4 ± 0.3 | 2.2 ± 0.3 |
| Leu4 | 1.3 ± 0.1 | 2.0 ± 0.2 |
| Lys4 | 0.3 ± 0.1 | 2.0 ± 0.7 |
| Met4 | 1.3 ± 0.1 | 2.1 ± 0.3 |
| Phe4 | 1.4 ± 0.2 | 2.5 ± 0.2 |
| Pro4 | No fit | |
| Ser4 | No fit | |
| Thr4 | 0.10 ± 0.02 | 2.0 ± 0.6 |
| Trp4 | 0.48 ± 0.03 | 1.4 ± 0.1 |
| Val4 | 1.7 ± 0.2 | 2.2 ± 0.2 |
| Ala1 | 0.19 ± 0.04 | 1.8 ± 0.8 |
| Ala1 + 4 | 2.3 ± 0.2 | 2.2 ± 0.1 |
| Ala3 + 4 | 2.4 ± 0.1 | 2.1 ± 0.1 |
| Ala4 + 5 | 1.7 ± 0.2 | 1.5 ± 0.1 |
| Ala4 + 7 | 0.38 ± 0.09 | 0.8 ± 0.2 |
| Ala4 + 9 | 0.09 ± 0.04 | 0.5 ± 0.3 |
| Tyr1 + 4 | 1.5 ± 0.1 | 1.2 ± 0.1 |
| Tyr2 + 4 | 2.1 ± 0.1 | 1.1 ± 0.1 |
| Tyr3 + 4 | 1.2 ± 0.1 | 2.4 ± 0.1 |
| Tyr4 + 5 | 1.4 ± 0.2 | 1.2 ± 0.1 |
| Tyr4 + 6 | 2.4 ± 0.2 | 1.2 ± 0.1 |
| Tyr4 + 7 | 1.0 ± 0.1 | 0.67 ± 0.05 |
| Tyr4 + 8 | 2.0 ± 0.3 | 0.92 ± 0.06 |
| Tyr1 + 3 | 1.4 ± 0.1 | 0.9 ± 0.1 |
| Tyr2 + 3 | 0.81 ± 0.03 | 1.1 ± 0.1 |
| Tyr3 + 5 | 0.7 ± 0.1 | 0.43 ± 0.03 |
| Tyr3 + 6 | 1.1 ± 0.1 | 0.62 ± 0.05 |
| Tyr3 + 7 | 0.97 ± 0.08 | 0.61 ± 0.03 |
| Tyr3 + 8 | 0.49 ± 0.07 | 0.39 ± 0.06 |
| Val1 + 4 | 2.3 ± 0.1 | 1.6 ± 0.1 |
| Val2 + 4 | 1.8 ± 0.1 | 1.2 ± 0.1 |
| Val3 + 4 | 1.6 ± 0.1 | 1.1 ± 0.1 |
| Val4 + 5 | 2.1 ± 0.1 | 1.5 ± 0.1 |
| Val4 + 6 | 1.4 ± 0.1 | 1.1 ± 0.1 |
| Val4 + 7 | 1.3 ± 0.1 | 0.93 ± 0.01 |
| Val4 + 8 | 1.0 ± 0.1 | 0.88 ± 0.06 |