Phenylmethylsulfonyl fluoride

In biochemistry, phenylmethane sulfonyl fluoride or phenylmethylsulfonyl fluoride ( PMSF , short for p henyl m ethane s ulfonyl f luoride or p henyl m ethyl s ulfonyl f luoride) is an inhibitor of serine proteases that is widely used in the isolation of protein extracts from various cells. PMSF does not inhibit all serine proteases ^{[ source? ]} . It quickly collapses in water, so in the initial ("stock") solutions, anhydrous ethanol , isopropanol , corn oil, or DMSO are usually used as a solvent. Inhibition of proteolytic enzymes occurs at a concentration of PMSF in the range from 0.1 to 1 millimole . The half-life in aqueous solutions (at 25 ° C) is 110 minutes at pH 7, 55 minutes at pH 7.5 and 35 minutes at pH 8. ^[1]

Phenylmethanesulfonyl fluoride (PMSF)
Are common
Chem. formula	C₇H₇FO₂S
Classification
Reg. CAS number
Pubchem
Reg. EINECS number
SMILES
Inchi
RTECS
CHEBI
Chemspider

PMSF binds specifically to serine residues of the actin center in serine proteases, but does not bind any other serine residues in the enzyme. This is a consequence of the hyperactivity of this serine residue, caused by specific environmental conditions in the active center of the enzyme. Since PMSF covalently binds to the enzyme, the complex can be visualized using X-ray crystallography ; therefore, PMSF can be used as a chemical label to identify serine in the active site of the enzyme.

Enzyme_ (active) -Ser-OH + F-SO ₂ CH ₂ C ₆ H ₅ → Enzyme-Ser-O-SO ₂ CH ₂ C ₆ H ₅ + HF

Serine protease + PMSF → irreversible complex Enzyme-PMS + HF

LD ₅₀ is less than 500 mg / kg ^[2] . PMSF is a cytotoxic chemical that should only be handled in a fume hood.