Hyytymisentsyymit

Hyytymisentsyymit, known in English as coagulation enzymes or clotting factors, are a group of proteins in the blood plasma that play a crucial role in hemostasis, the process of stopping bleeding. When a blood vessel is injured, these enzymes are activated in a cascade, a series of enzymatic reactions where one enzyme activates the next. This cascade leads to the formation of a fibrin clot, which seals the damaged vessel and prevents further blood loss.

The coagulation cascade is traditionally divided into two pathways: the intrinsic and extrinsic pathways. The intrinsic pathway is activated by damage within the blood vessel itself, while the extrinsic pathway is initiated by external trauma that exposes tissue factor. Both pathways converge on a common pathway that ultimately leads to the conversion of fibrinogen, a soluble protein, into fibrin, an insoluble protein that forms the meshwork of the clot.

Many of the coagulation enzymes are serine proteases, meaning they have a serine residue in their active site. They are often produced in the liver and require vitamin K for their synthesis. Deficiencies in specific coagulation enzymes can lead to bleeding disorders, such as hemophilia, where the blood does not clot properly, increasing the risk of excessive bleeding. Conversely, overactivity of the clotting system can lead to thrombosis, the formation of unwanted blood clots within blood vessels.