Zymogen
Zymogens (or proenzymes ) are inactive enzyme precursors . Examples are pepsinogen or chymotrypsinogen . In contrast to apoenzymes , they are converted into the active form by proteases ( proteolysis ) or the enzyme itself ( autoproteolysis ). It differs from apoenzymes in that this post-translational modification breaks covalent bonds. Zymogens are a special case of a precursor protein .
Zymogens are important in the digestive processes because the enzyme, if it were already active during transport to the actual site of action, could possibly attack other enzymes or structural proteins in the body.
An example of a disease caused by the premature activation of digestive enzymes is pancreatitis (inflammation of the pancreas), in which, due to a blockage of the bile duct in the area of the common mouth, the enzymes formed by the pancreas are activated before the digestive tract , and thus the pancreas or the damage surrounding tissues.
Zymogens are of particular importance as coagulation factors , precursors of the active coagulation enzymes that cascade into the blood coagulation system. In addition, the process of zymogen activation is found in the immune response in many factors of the complement system .
Individual evidence
- ↑ Zymogen. In: UniProt Keywords. UniProtKB, accessed on September 10, 2010 : “Definition. The enzymatically inactive precursor of mostly proteolytic enzymes. Synonyms. Proenzymes "
- ↑ Mary K. Campbell, Shawn O. Farrell: Biochemistry . Brooks Cole, 2007, ISBN 0-495-39041-0 , pp. 182 ff .