1 M IPTG recipe
The inducer that switches on lac-promoter expression: 0.1–1 mM for expression, 0.1 mM in blue/white plates.
🧮 Volume calculator
| Component | Amount | Final concentration (1X) |
|---|---|---|
| IPTG (isopropyl β-D-1-thiogalactopyranoside) | 2.383 g | 1 M |
| Water (distilled) | to final volume |
Steps
- Dissolve in water and bring to volume.
- Filter-sterilise through 0.22 µm. Aliquot and store at −20 °C.
Good to know
- Induce at OD600 0.5–0.8; for insoluble proteins, express overnight at 16–25 °C to improve solubility.
FAQ
How much in blue/white plates?
Add 100 µL of 1 M IPTG per litre (0.1 mM) with 40 µg/mL X-gal, or spread 40 µL of 100 mM IPTG on a finished plate.
This is a widely used standard composition. Amounts depend on the hydrate form and purity of your reagents — check the formula weight (FW) on the bottle and follow your institution's safety rules and the manufacturers' instructions.