100 mM PMSF recipe
A serine-protease inhibitor. It breaks down quickly in water, so keep it in isopropanol and add 1:100 (1 mM final) right before lysis.
🧮 Volume calculator
| Component | Amount | Final concentration (1X) |
|---|---|---|
| PMSF | 174.2 mg | 100 mM |
| Isopropanol (or absolute ethanol) | to final volume |
Steps
- Dissolve PMSF in isopropanol and make up to volume.
- Store in a dark tube at −20 °C (or room temperature).
- Add to lysis buffer at 1:100 immediately before use.
Good to know
- Its half-life in water is about 35 min at pH 8 — adding it in advance is useless.
- Crystals may form in the cold; warm and mix to redissolve.
⚠ Safety PMSF is highly toxic (a cholinesterase inhibitor). Wear gloves and avoid inhaling the powder.
FAQ
Do I need PMSF if I use a commercial inhibitor cocktail?
Most cocktails already contain a serine-protease inhibitor (e.g. AEBSF), so PMSF is optional.
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.