Table 1.
Summary of purification of the 45-kDa PTTH
| Purification procedure | Total protein, mg | Critical dose, μg | Specific activity,* unit/mg | Total activity,* unit | Yield, % | Purification, -fold |
|---|---|---|---|---|---|---|
| Acetone powder | 1.72 × 105 | — | — | — | — | — |
| 2% NaCl extract | 1.60 × 103 | — | — | — | — | — |
| Heat treatment | 340.00 | 8.0 | 125 | 42,500 | 100.00 | 1.00 |
| Q-Sepharose | 31.00 | 4.1 | 244 | 7,600 | 17.80 | 1.95 |
| S-Sepharose | 4.00 | 0.8 | 1,250 | 5,000 | 11.80 | 10.00 |
| HPLC | 1.00 | 0.5 | 2,000 | 2,000 | 4.71 | 16.00 |
| Superdex G-75 | 0.05 | 0.1 | 10,000 | 500 | 1.20 | 80.00 |
Third instar larvae of D. melanogaster, 4 × 105 (0.8 kg) were used as starting material.
*
One unit (i.e., critical dose) corresponds to the amount of hormone that is required to increase the ecdysone Ar from 1 to 2 during a 2-hr incubation.