Table 1.
Protein quantitation
| Target peptide | MW (kD) | Aggregate yielda (μg/mg wet cell pellet) | Peptide yieldb (μg/mg wet cell pellet) | Cleavage efficiencyc (%) | Percent recoveryd (%) |
|---|---|---|---|---|---|
| pET-P-Intein-ELK16 | |||||
| GLP-1 | 3.5 | 31.1 | 1.8 | 60.9 | 46.8 |
| IGF-1αe | 7.8 | 35.4 | 5.2 | 70.6 | 62.0 |
| CCL5e | 7.8 | 35.5 | 5.2 | 70.9 | 61.3 |
| SDF-1αe | 8.0 | 28.4 | 3.5 | 53.3 | 50.7 |
| Leptine | 16.2 | 44.6 | 10.5 | 60.3 | 60.3 |
| pET-Trx-P-Intein-ELK16 | |||||
| Trx-GLP-1 | 16.9 | 52.4 | 9.7 | 57.4 | 46.2 |
| Trx-IGF-1α | 21.2 | 34.0 | 9.2 | 67.8 | 59.4 |
| Trx-CCL5 | 21.2 | 57.8 | 7.0 | 44.8 | 26.5 |
| Trx-SDF-1α | 21.2 | 56.5 | 5.0 | 35.3 | 19.3 |
| Trx-BNP | 17.0 | 49.9 | 13.4 | 67.1 | 66.6 |
| Trx-Ex-4 | 17.7 | 11.4 | 3.4 | 75.3 | 73.1 |
aYield of protein aggregate
bYield of free target peptide after intein-mediated cleavage from LB culture with wet cell weight of 2.66 ± 0.99 mg/mL, estimated by densitometry analysis software Quantity One
cCleavage efficiency as calculated by dividing the amount of cleaved protein aggregate over that of the total aggregate before cleavage
dPercent recovery in terms of mass as calculated by dividing the mass of the free peptide after cleavage over that could be theoretically obtained from the respective protein aggregate, assuming a complete cleavage and release
eThe peptides were in the insoluble fraction after intein-mediated cleavage