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Kallikreins
Kallikreins are a subgroup of serine proteases, enzymes capable of cleaving peptide bonds in proteins. In humans, plasma kallikrein (encoded by ''KLKB1 gene'') has no known paralogue, while tissue kallikrein-related peptidases (''KLKs'') encode a family of fifteen closely related serine proteases. These genes are localised to chromosome 19q13, forming the largest contiguous cluster of proteases within the human genome. Kallikreins are responsible for the coordination of various physiological functions including blood pressure, semen liquefaction and skin desquamation. Occurrence In 1934, Eugen Werle reported finding a substance in the pancreas of humans and various animals in such large amounts that the pancreas could be taken for its site of origin. He named it kallikrein, by derivation from the Greek word for pancreas. Since then, similar enzymes have been found in the biological fluids of humans and other mammals, as well as in some snake venoms. Venom The caterpillar kno ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
KLK2
Kallikrein-2 is a protein that in humans is encoded by the ''KLK2'' gene, and is particularly associated with prostatic tissue. References Further reading * * * * * * * * * * * * * * * * * * * External links * The MEROPS MEROPS is an online database for peptidases (also known as proteases, proteinases and proteolytic enzymes) and their inhibitors. The classification scheme for peptidases was published by Rawlings & Barrett in 1993, and that for protein inhibi ... online database for peptidases and their inhibitorsS01.161 * {{gene-19-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
KLK1
Kallikrein-1 is a protein that in humans is encoded by the ''KLK1'' gene. KLK1 is a member of the peptidase S1 family. Kallikreins are a subgroup of serine proteases having diverse physiological functions. Growing evidence suggests that many kallikreins are implicated in carcinogenesis and some have potential as novel cancer and other disease biomarkers. This gene is one of the fifteen kallikrein subfamily members located in a cluster on chromosome 19. This protein is functionally conserved in its capacity to release the vasoactive peptide, Lys-bradykinin, from low molecular weight kininogen. See also * Kinin–kallikrein system * Kininogen 1 References Further reading * * * * * * * * * * * * * * * * * * * External links * The MEROPS MEROPS is an online database for peptidases (also known as proteases, proteinases and proteolytic enzymes) and their inhibitors. The classification scheme for peptidases was published by Rawlings & Barrett in 1993, and that for protei ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
KLK12
Kallikrein-12 is a protein that in humans is encoded by the ''KLK12'' gene. Kallikreins are a subgroup of serine proteases having diverse physiological functions. Growing evidence suggests that many kallikreins are implicated in carcinogenesis and some have potential as novel cancer and other disease biomarkers. This gene is one of the fifteen kallikrein subfamily members located in a cluster on chromosome 19. Alternate splicing of this gene results in three transcript variants encoding different isoforms. References Further reading * * * * * * * * * * * External links * The MEROPS MEROPS is an online database for peptidases (also known as proteases, proteinases and proteolytic enzymes) and their inhibitors. The classification scheme for peptidases was published by Rawlings & Barrett in 1993, and that for protein inhibi ... online database for peptidases and their inhibitorsS01.020 {{gene-19-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solenodon
Solenodons (from el, τέλειος , 'channel' or 'pipe' and el, ὀδούς , 'tooth') are venomous, nocturnal, burrowing, insectivorous mammals belonging to the family Solenodontidae . The two living solenodon species are the Cuban solenodon (''Atopogale cubana''), and the Hispaniolan solenodon (''Solenodon paradoxus''). Threats to both species include habitat destruction and predation by non-native cats, dogs, and mongooses, introduced by humans to the solenodons' home islands to control snakes and rodents. The Hispaniolan solenodon covers a wide range of habitats on the island of Hispaniola from lowland dry forest to highland pine forest. Two other described species became extinct during the Quaternary. Oligocene North American genera, such as '' Apternodus'', have been suggested as relatives of ''Solenodon'', but the origins of the animal remain obscure. Two genera, '' Atopogale'' and '' Solenodon'', are known, each with one extant species. Other genera have b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
KLK3
Prostate-specific antigen (PSA), also known as gamma-seminoprotein or kallikrein-3 (KLK3), P-30 antigen, is a glycoprotein enzyme encoded in humans by the ''KLK3'' gene. PSA is a member of the kallikrein-related peptidase family and is secreted by the epithelial cells of the prostate gland. PSA is produced for the ejaculate, where it liquefies semen in the seminal coagulum and allows sperm to swim freely. It is also believed to be instrumental in dissolving cervical mucus, allowing the entry of sperm into the uterus. PSA is present in small quantities in the serum of men with healthy prostates, but is often elevated in the presence of prostate cancer or other prostate disorders. PSA is not uniquely an indicator of prostate cancer, but may also detect prostatitis or benign prostatic hyperplasia. Medical uses Prostate cancer Screening Clinical practice guidelines for prostate cancer screening vary and are controversial, in part due to uncertainty as to whether the ben ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kininogen
Kininogens are precursor proteins for kinins, biologically active polypeptides involved in blood coagulation, vasodilation, smooth muscle contraction, inflammatory regulation, and the regulation of the cardiovascular and renal systems. Types of kininogen There are two main types of kininogen (KNG), high-molecular-weight-kininogen and low-molecular-weight-kininogen, with a third type – T-kininogen – only found in rats but not humans. High molecular weight kininogen High-molecular-weight-kininogen (HK) is a non-enzymatic cofactor involved in the kinin-kallikrein system, which plays a role in blood coagulation, blood pressure regulation, and inflammation. It is synthesized in endothelial cells and is produced mostly by the liver. It is also a precursor protein for bradykinin. Low molecular weight kininogen Low-molecular-weight-kininogen (LK) is mainly a precursor protein for kallidin. LK, however, is not actively involved in blood coagulation, but its byproducts ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kinin
A kinin is any of various structurally related polypeptides, such as bradykinin and kallidin. They are members of the autacoid family. Kinins are peptides that are cleaved from kininogens by the process of kallikreins. Kallikreins activate kinins when stimulated. It is a component of the kinin-kallikrein system. Their precursors are kininogens. Kininogens contain a 9-11 amino acid bradykinin sequence. In botany, the plant hormones known as cytokinins were first called kinins, but the name was changed to avoid confusion. Effects of Kinins Kinin are short lived peptides that cause pain sensation, arteriolar dilation, increase vascular permeability and cause contractions in smooth muscle. Kinins transmit their effects through G protein- coupled receptors. Kinin act on axons to block nervous impulses, which leads to distal muscle relaxation. Kinin are also potent nerve stimulators. which is mostly responsible for the sense of pain (and sometimes itching). Kinin increase vascula ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Factor XII
Coagulation factor XII, also known as Hageman factor, is a plasma protein. It is the zymogen form of factor XIIa, an enzyme () of the serine protease (or serine endopeptidase) class. In humans, factor XII is encoded by the ''F12'' gene. Structure Human Factor XII is 596 amino acids long and consists of two chains, the heavy chain (353 residues) and light chain (243 residues) held together by a disulfide bond. It is 80,000 daltons. Its heavy chain contains two fibronectin-type domains (type I and II), two epidermal growth factor-like domains, a kringle domain, and a proline-rich region, and its light chain contains the protease domain. The structure of the FnI-EGF-like tandem domain of coagulation factor XII has been solved by X-ray crystallography. Crystal structures of the FXII light chain has also been determined unbound (β-FXII) and bound (β-FXIIa) to inhibitors. Factor XII (FXII, Hageman factor) is a plasma glycoprotein of approximately 90 kDa molecular weight is par ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PAN Domain
PAN domains have significant functional versatility fulfilling diverse biological roles by mediating protein-protein and protein-carbohydrate interactions. These domains contain a hair-pin loop like structure, similar to that found in knottins but with a different pattern of disulfide bonds. It has been shown that the N-terminal domains of members of the plasminogen/hepatocyte growth factor family, the apple domains of the plasma prekallikrein/ coagulation factor XI family, and domains of various nematode proteins belong to the same module superfamily, the PAN module. The PAN domain contains a conserved core of three disulfide bridges. In some members of the family there is an additional fourth disulfide bridge that links the N- and C-termini of the domain. The apple domain, as well as other examples of the PAN domain, consists of 7 β-strands that fold into a curved antiparallel sheet cradling an α-helix. Two disulfide bonds lock the helix onto the central β4 and β5 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Factor XI
Factor XI or plasma thromboplastin antecedent is the zymogen form of factor XIa, one of the enzymes of the coagulation cascade. Like many other coagulation factors, it is a serine protease. In humans, Factor XI is encoded by the ''F11'' gene. Function Factor XI (FXI) is produced by the liver and circulates as a homo-dimer in its inactive form. The plasma half-life of FXI is approximately 52 hours. The zymogen factor is activated into ''factor XIa'' by factor XIIa (FXIIa), thrombin, and FXIa itself; due to its activation by FXIIa, FXI is a member of the "contact pathway" (which includes HMWK, prekallikrein, factor XII, factor XI, and factor IX). Factor XIa activates factor IX by selectively cleaving arg- ala and arg-val peptide bonds. Factor IXa, in turn, forms a complex with Factor VIIIa (FIXa-FVIIIa) and activates factor X. Physiological inhibitors of factor XIa include protein Z-dependent protease inhibitor (ZPI, a member of the serine protease inhibitor/se ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fibrinolysis
Fibrinolysis is a process that prevents blood clots from growing and becoming problematic. Primary fibrinolysis is a normal body process, while secondary fibrinolysis is the breakdown of clots due to a medicine, a medical disorder, or some other cause.Dugdale, David et al.Primary or secondary fibrinolysis, Medline Plus. Retrieved 7 August 2011. In fibrinolysis, a fibrin clot, the product of coagulation, is broken down. Its main enzyme plasmin cuts the fibrin mesh at various places, leading to the production of circulating fragments that are cleared by other proteases or by the kidney and liver. Physiology Plasmin is produced in an inactive form, plasminogen, in the liver. Although plasminogen cannot cleave fibrin, it still has an affinity for it, and is incorporated into the clot when it is formed. Tissue plasminogen activator (t-PA) and urokinase are the agents that convert plasminogen to the active plasmin, thus allowing fibrinolysis to occur. t-PA is released into the blood ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plasminogen
Plasmin is an important enzyme () present in blood that degrades many blood plasma proteins, including fibrin clots. The degradation of fibrin is termed fibrinolysis. In humans, the plasmin protein (in the zymogen form of plasminogen) is encoded by the ''PLG'' gene. Function Plasmin is a serine protease that acts to dissolve fibrin blood clots. Apart from fibrinolysis, plasmin proteolyses proteins in various other systems: It activates collagenases, some mediators of the complement system, and weakens the wall of the Graafian follicle, leading to ovulation. Plasmin is also integrally involved in inflammation. It cleaves fibrin, fibronectin, thrombospondin, laminin, and von Willebrand factor. Plasmin, like trypsin, belongs to the family of serine proteases. Plasmin is released as a zymogen called plasminogen (PLG) from the liver into the systemic circulation. Two major glycoforms of plasminogen are present in humans - type I plasminogen contains two glycosylatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
