PMSF
Encyclopedia
In biochemistry
, PMSF (phenylmethanesulfonylfluoride or phenylmethylsulfonyl fluoride) is a serine protease inhibitor commonly used in the preparation of cell lysates. PMSF does not inhibit all serine protease
s. It is rapidly degraded in water and stock solutions are usually made up in anhydrous ethanol
, isopropanol, corn oil
, or DMSO
. Proteolytic inhibition occurs when a concentration between 0.1 - 1 mM PMSF is used. The half-life is short in aqueous solutions (110 min at pH 7, 55 min at pH 7.5, and 35 min at pH 8, all at 25°C).
PMSF binds specifically to the active site serine
residue in a serine protease. It does not bind to any other serine residues in the protein. This is a result of the hyperactivity of that serine residue caused by the specific environmental conditions in the enzyme's active site. Because PMSF binds covalently to the enzyme, the complex can be viewed by X-ray crystallography; it can therefore be used as a chemical label to identify an essential active site SER in an enzyme.
The is less than 500 mg/kg. PMSF is a cytotoxic chemical which should be handled only inside a fume hood.
PMSF is commonly used in protein solublization in order to deactivate proteases from digesting proteins of interest after cell lysis.
Biochemistry
Biochemistry, sometimes called biological chemistry, is the study of chemical processes in living organisms, including, but not limited to, living matter. Biochemistry governs all living organisms and living processes...
, PMSF (phenylmethanesulfonylfluoride or phenylmethylsulfonyl fluoride) is a serine protease inhibitor commonly used in the preparation of cell lysates. PMSF does not inhibit all serine protease
Serine protease
Serine proteases are enzymes that cleave peptide bonds in proteins, in which serine serves as the nucleophilic amino acid at the active site.They are found ubiquitously in both eukaryotes and prokaryotes...
s. It is rapidly degraded in water and stock solutions are usually made up in anhydrous ethanol
Ethanol
Ethanol, also called ethyl alcohol, pure alcohol, grain alcohol, or drinking alcohol, is a volatile, flammable, colorless liquid. It is a psychoactive drug and one of the oldest recreational drugs. Best known as the type of alcohol found in alcoholic beverages, it is also used in thermometers, as a...
, isopropanol, corn oil
Corn oil
Corn oil is oil extracted from the germ of corn . Its main use is in cooking, where its high smoke point makes refined corn oil a valuable frying oil. It is also a key ingredient in some margarines. Corn oil is generally less expensive than most other types of vegetable oils. One bushel of corn...
, or DMSO
Dimethyl sulfoxide
Dimethyl sulfoxide is an organosulfur compound with the formula 2SO. This colorless liquid is an important polar aprotic solvent that dissolves both polar and nonpolar compounds and is miscible in a wide range of organic solvents as well as water...
. Proteolytic inhibition occurs when a concentration between 0.1 - 1 mM PMSF is used. The half-life is short in aqueous solutions (110 min at pH 7, 55 min at pH 7.5, and 35 min at pH 8, all at 25°C).
PMSF binds specifically to the active site serine
Serine
Serine is an amino acid with the formula HO2CCHCH2OH. It is one of the proteinogenic amino acids. By virtue of the hydroxyl group, serine is classified as a polar amino acid.-Occurrence and biosynthesis:...
residue in a serine protease. It does not bind to any other serine residues in the protein. This is a result of the hyperactivity of that serine residue caused by the specific environmental conditions in the enzyme's active site. Because PMSF binds covalently to the enzyme, the complex can be viewed by X-ray crystallography; it can therefore be used as a chemical label to identify an essential active site SER in an enzyme.
- Enzyme(active)Ser-O-H + F-SO2CH2C6H5 → EnzymeSer-O-SO2CH2C6H5 + HF
- Serine protease + PMSF → Irreversible enzyme-PMS complex + HF
The is less than 500 mg/kg. PMSF is a cytotoxic chemical which should be handled only inside a fume hood.
PMSF is commonly used in protein solublization in order to deactivate proteases from digesting proteins of interest after cell lysis.
External links
- The MEROPSMeropsMerops may refer to:* Merops , a genus of bee-eaters.* MEROPS, an on-line database for peptidases.It may also refer to several figures from Greek mythology:* King of Ethiopia, husband of Clymene, who lay with Helios and bore Phaethon...
online database for peptidases and their inhibitors: PMSF