What is PMSF?

PMSF or phenylmethanesulphonylfluoride or phenylmethylsulphonyl fluoride is serine protease inhibitor. It is regular ingredient of most of the protein preparations.

Preparation of PMSF solution

PMSF is normally unstable in aqueous solutions. But highly stable and soluble in non-polar organic solvents like isopropanol, methanol, ethanol etc.

PMSF is soluble (>= 1M) in polar organic solvents such as isopropanol, methanol, ethanol, and 1,2 propanediol. A stock solution of PMSF in 100% isopropanol is stable at least 9 months at 25degC. Stability and solubility in aqueous solution: PMSF is sparingly soluble (slightly greater than 1mM, 25degC) in aqueous buffers. It is also very_ unstable. Aqueous solutions of PMSF are inactivated rapidly (hydrolyzed), an effect accelerated by rising pHG and temperature. The half-life of 100uM PMSF at 25degC (measured as ability to inhibit chymotrypsin) is 110 min. at pH 7.0 (phosphate buffer), 55min. at pH 7.5 (Hepes), and 35 minutes at pH 8.0 (Tris). At 4degC, 100uM PMSF is completely inactivated in 30h at pH 7.6 (Hepes), 22h at pH 8.0 (Tris), and 10h at pH 8.6 (Tris). Presence of EDTA and other metal chelators, DTT or 2-mercaptoethanol does not interfere with the action of PMSF.

The white crystal is fairly stable at room temperature.

PMSF (10mg/ml in isopropanol), working concentration 17-174ug/ml (100-100uM). Stable at 25C for 9 months.

References

1) Fahrney and Gold, J Am Chem Soc 85: 997-100 (1963)

2) Gold and Fahrney, Biochemistry 3: 783-791 (1964)

3) Turini, et al., J Pharmacol Exp Ther 167: 98-104 (1969)

4) Gold, Methods Enzymol 11: 706-711 (1967)

5) James. Anal Biochem 86: 574-579 (1978)