Serine protease

Serine proteases are a sub-family of peptidases (ie enzymes which cleave proteins and peptides ).

The classification in this group refers to the active site of peptidases. Like all enzymes have also serine proteases a very specific structure in the active site, where the catalytic triad. In the serine proteases is found there, the amino acid serine.

Serine proteases belonging to the digestive enzymes trypsin, chymotrypsin, elastase, and plasmin and thrombin, both of which assume an important role in the blood coagulation.

Catalyzed reaction

Inhibition

Inhibition of serine proteases found in the body rather than for example, certain proteins that serpins to disable the serine protease after work. An absence of these inhibitors leads to thrombosis ( eg antithrombin ) or emphysema (Example antitrypsin ). In such cases, man-made inhibitors can be given, such as AEBSF and phenylmethylsulfonyl fluoride.

The serine proteases are a highly differentiated control by a network of interacting cascades of inhibitors. There are two forms are distinguished.

Non-specific inhibition

A form of inhibition of proteases is the envelope by a cage. The alpha-2 -macroglobulin embraces activated proteases, such as a mousetrap. Serine proteases such as thrombin and prekallikrein are inactivated.

Specific inhibition

Another form of inhibition of serine proteases is a highly specific by serpins, a class of serine protease inhibitors. Many enzymes of the coagulation system serine proteases and serine protease are those inhibitors.

Classification according to UniProt / MEROPS

The UniProt Consortium regularly publishes a list of peptidases which categorizes these enzymes according to their evolutionary descent. The data in the list are provided with quality information, in the MEROPS database available. Closely related molecules are grouped into families whose identifiers consist of a letter ( 'S' for serine proteases ) and a number. Families in turn belong to clans whose families are related. Clan identifiers instead of numbers have a letter.

There are 45 serine protease families in 13 clans (as of 2008 ), where the clan PA (S ) with 12 families, play an outstanding importance.

Important serine proteases

• The digestive enzymes trypsin, chymotrypsin, elastase (S1)
• Prostate-specific antigen and tryptases (S1 )
• Blood coagulation factors, plasmin, thrombin, Christmas factor, Hageman factor, factor VII- activating protease, kallikrein (S1) and Stuart - Prower factor (S2)
• MBTPS1 and proteinase K ( S8)
• Dipeptidyl peptidase 4 (S9 )