Kallikrein: Difference between revisions

Latest revision as of 01:05, 20 February 2025

Kallikrein is a subgroup of serine proteases that are involved in various physiological processes, including blood coagulation, inflammation, and fibrinolysis. These enzymes are known for their ability to cleave peptide bonds in proteins, thereby activating or inactivating them.

Structure and Function[edit]

Kallikreins are characterized by their serine protease activity, which means they have a serine residue at their active site that plays a crucial role in their enzymatic function. They are synthesized as inactive precursors called zymogens and are activated by proteolytic cleavage.

Kallikreins are involved in the kinin-kallikrein system, where they cleave kininogen to release bradykinin, a peptide that causes blood vessels to dilate and lowers blood pressure. This system plays a significant role in the regulation of blood pressure, inflammation, and pain.

Types of Kallikreins[edit]

There are two main types of kallikreins:

Plasma kallikrein: This type circulates in the blood and is involved in the intrinsic pathway of the coagulation cascade. It also plays a role in the activation of the complement system.

Tissue kallikrein: Found in various tissues, this type is involved in the local generation of kinins and other biologically active peptides.

Role in Fibrinolysis[edit]

Kallikrein plays a crucial role in the process of fibrinolysis, which is the breakdown of fibrin in blood clots. It activates plasminogen to plasmin, the enzyme responsible for degrading fibrin. This process is essential for maintaining blood flow and preventing thrombosis.

Clinical Significance[edit]

Dysregulation of kallikrein activity can lead to various medical conditions. For example, excessive kallikrein activity can result in hereditary angioedema, a condition characterized by episodes of severe swelling. Conversely, insufficient kallikrein activity can contribute to hypertension and thrombosis.

Kallikreins are also being studied as potential biomarkers for certain cancers, such as prostate cancer, where kallikrein-related peptidase 3 (KLK3), also known as prostate-specific antigen (PSA), is used in screening and monitoring.

Related Pages[edit]

Kallikrein

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-'''Kallikrein''' is a group of enzymes known as serine proteases that are found in various tissues and body fluids. They play a crucial role in the regulation of different physiological processes such as blood pressure, inflammation, and coagulation.
+'''Kallikrein''' is a subgroup of serine proteases that are involved in various physiological processes, including blood coagulation, inflammation, and [[fibrinolysis]]. These enzymes are known for their ability to cleave peptide bonds in proteins, thereby activating or inactivating them.
-== Function ==
+== Structure and Function ==
+Kallikreins are characterized by their serine protease activity, which means they have a serine residue at their active site that plays a crucial role in their enzymatic function. They are synthesized as inactive precursors called zymogens and are activated by proteolytic cleavage.
-Kallikreins are involved in the regulation of several physiological processes. They are known to regulate blood pressure by acting on the [[kinin-kallikrein system]], where they cleave kininogen to release bradykinin. Bradykinin is a potent vasodilator that helps in lowering blood pressure.
+Kallikreins are involved in the [[kinin-kallikrein system]], where they cleave kininogen to release [[bradykinin]], a peptide that causes blood vessels to dilate and lowers blood pressure. This system plays a significant role in the regulation of blood pressure, inflammation, and pain.
-Kallikreins also play a role in inflammation. They are involved in the activation of the complement system, which is a part of the immune system that enhances the ability of antibodies and phagocytic cells to clear microbes and damaged cells from an organism.
+== Types of Kallikreins ==
+There are two main types of kallikreins:
-In addition, kallikreins are involved in the coagulation process. They activate factor XII, which is a part of the coagulation cascade that leads to the formation of a blood clot.
+* '''Plasma kallikrein''': This type circulates in the blood and is involved in the intrinsic pathway of the coagulation cascade. It also plays a role in the activation of the complement system.
-== Types ==
+* '''Tissue kallikrein''': Found in various tissues, this type is involved in the local generation of kinins and other biologically active peptides.
-There are two types of kallikreins: tissue kallikrein and plasma kallikrein.
+== Role in Fibrinolysis ==
+Kallikrein plays a crucial role in the process of fibrinolysis, which is the breakdown of fibrin in blood clots. It activates plasminogen to plasmin, the enzyme responsible for degrading fibrin. This process is essential for maintaining blood flow and preventing thrombosis.
-Tissue kallikrein is found in various tissues including the pancreas, salivary glands, and kidneys. It is involved in the regulation of blood pressure and electrolyte balance.
+== Clinical Significance ==
+Dysregulation of kallikrein activity can lead to various medical conditions. For example, excessive kallikrein activity can result in hereditary angioedema, a condition characterized by episodes of severe swelling. Conversely, insufficient kallikrein activity can contribute to hypertension and thrombosis.
-Plasma kallikrein is found in the blood and is involved in the coagulation process. It is also involved in the regulation of inflammation and blood pressure.
+Kallikreins are also being studied as potential biomarkers for certain cancers, such as prostate cancer, where kallikrein-related peptidase 3 (KLK3), also known as [[prostate-specific antigen]] (PSA), is used in screening and monitoring.
-== Clinical significance ==
-Abnormal levels of kallikrein can lead to various health conditions. High levels of kallikrein can lead to conditions such as hereditary angioedema, a rare genetic disorder that causes swelling in various parts of the body. On the other hand, low levels of kallikrein can lead to conditions such as hypertension.
-Kallikrein is also used as a biomarker in the diagnosis of various cancers. High levels of kallikrein in the blood can indicate the presence of cancers such as prostate cancer and ovarian cancer.
-== See also ==
+== Related Pages ==
+* [[Serine protease]]
 * [[Kinin-kallikrein system]]
+* [[Fibrinolysis]]
 * [[Bradykinin]]
-* [[Hereditary angioedema]]
+* [[Prostate-specific antigen]]
-* [[Hypertension]]
-* [[Prostate cancer]]
-* [[Ovarian cancer]]
+[[Category:Proteases]]
 [[Category:Enzymes]]
-[[Category:Physiology]]
+<gallery>
-[[Category:Medical terms]]
+File:Fibrinolysis.svg|Kallikrein
-[[Category:Biochemistry]]
+</gallery>
-{{stub}}