Kinin

Kinin is a group of polypeptides that are involved in various physiological and pathological processes. They are part of the Kallikrein-Kinin System and are known for their ability to cause dilation of blood vessels, contraction of smooth muscle, and pain when injected into the skin.

Overview

Kinin is derived from the precursor molecule kininogen through the action of the enzyme kallikrein. There are two main types of kinins: bradykinin and kallidin, which are both nonapeptides. They are metabolized by the enzyme kininase.

Function

Kinin plays a crucial role in many physiological processes, including the regulation of blood pressure, the control of smooth muscle contraction, and the modulation of pain perception. It is also involved in the inflammatory response, as it can increase vascular permeability and stimulate the release of other inflammatory mediators.

Clinical significance

Abnormalities in the kinin system have been implicated in a number of diseases, including hypertension, asthma, and autoimmune diseases. In addition, kinins have been found to play a role in the pathogenesis of sepsis and shock.

See also

• Kallikrein
• Kininogen
• Bradykinin
• Kallidin
• Kininase