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Kinin–kallikrein System
The kinin–kallikrein system or simply kinin system is a poorly understood hormonal system with limited available research. It consists of blood proteins that play a role in inflammation, blood pressure control, coagulation and pain. Its important mediators bradykinin and kallidin are vasodilators and act on many cell types. Clinical symptoms include marked weakness, tachycardia, fever, leukocytosis and acceleration of ESR. History The system was discovered in 1909 when researchers discovered that injection with urine (high in kinins) led to hypotension (low blood pressure). The researchers Emil Karl Frey, Heinrich Kraut and Eugen Werle discovered high-molecular weight kininogen in urine around 1930. Etymology kinin kkīn(eîn) to move, set in motion. kallikrein k kalli~ sweet and krein = kreos, flesh, named for the pancreatic extracts where it was first discovered Members The system consists of a number of large proteins, some small polypeptides and a group of enzymes th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hormonal System
The endocrine system is a messenger system in an organism comprising feedback loops of hormones that are released by internal glands directly into the circulatory system and that target and regulate distant Organ (biology), organs. In vertebrates, the hypothalamus is the neural control center for all endocrine systems. In humans, the major endocrine glands are the thyroid gland, thyroid, parathyroid gland, parathyroid, pituitary gland, pituitary, pineal gland, pineal, and adrenal glands, and the (male) testis and (female) ovaries. The hypothalamus, pancreas, and thymus also function as endocrine glands, among other functions. (The hypothalamus and pituitary glands are organs of the Neuroendocrinology#Neuroendocrine system, neuroendocrine system. One of the most important functions of the hypothalamusit is located in the brain adjacent to the pituitary glandis to link the endocrine system to the nervous system via the pituitary gland.) Other organs, such as the kidneys, also have ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Low-molecular Weight Kininogen
Low-molecular-weight kininogen is a form of kininogen, which has been identified in mice, guinea pigs, and whale Whales are a widely distributed and diverse group of fully Aquatic animal, aquatic placental mammal, placental marine mammals. As an informal and Colloquialism, colloquial grouping, they correspond to large members of the infraorder Cetacea ...s. It is also found in humans. References External links * {{Coagulation Kinin–kallikrein system ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carboxy-terminus
The C-terminus (also known as the carboxyl-terminus, carboxy-terminus, C-terminal tail, carboxy tail, C-terminal end, or COOH-terminus) is the end of an amino acid chain (protein or polypeptide), terminated by a free carboxyl group (-COOH). When the protein is translated from messenger RNA, it is created from N-terminus to C-terminus. The convention for writing peptide sequences is to put the C-terminal end on the right and write the sequence from N- to C-terminus. Chemistry Each amino acid has a carboxyl group and an amine group. Amino acids link to one another to form a chain by a dehydration reaction which joins the amine group of one amino acid to the carboxyl group of the next. Thus polypeptide chains have an end with an unbound carboxyl group, the C-terminus, and an end with an unbound amine group, the N-terminus. Proteins are naturally synthesized starting from the N-terminus and ending at the C-terminus. Function C-terminal retention signals While the N-terminus of a prote ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arginine
Arginine is the amino acid with the formula (H2N)(HN)CN(H)(CH2)3CH(NH2)CO2H. The molecule features a guanidinium, guanidino group appended to a standard amino acid framework. At physiological pH, the carboxylic acid is deprotonated (−CO2−) and both the amino and guanidino groups are protonated, resulting in a cation. Only the -arginine (symbol Arg or R) enantiomer is found naturally. Arg residues are common components of proteins. It is Genetic code, encoded by the DNA codon table, codons CGU, CGC, CGA, CGG, AGA, and AGG. The guanidine group in arginine is the Precursor (chemistry), precursor for the biosynthesis of nitric oxide. Like all amino acids, it is a white, water-soluble solid. The one-letter symbol R was assigned to arginine for its phonetic similarity. History Arginine was first isolated in 1886 from Lupinus luteus, yellow lupin seedlings by the German chemist Ernst Schulze (chemist), Ernst Schulze and his assistant Ernst Steiger. He named it from the Greek ''árg ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carboxypeptidase
A carboxypeptidase ( EC number 3.4.16 - 3.4.18) is a protease enzyme that hydrolyzes (cleaves) a peptide bond at the carboxy-terminal (C-terminal) end of a protein or peptide. This is in contrast to an aminopeptidases, which cleave peptide bonds at the N-terminus of proteins. Humans, animals, bacteria and plants contain several types of carboxypeptidases that have diverse functions ranging from catabolism to protein maturation. At least two mechanisms have been discussed. Functions Initial studies on carboxypeptidases focused on pancreatic carboxypeptidases A1, A2, and B in the digestion of food. Most carboxypeptidases are not, however, involved in catabolism. Instead they help to mature proteins, for example post-translational modification. They also regulate biological processes, such as the biosynthesis of neuroendocrine peptides such as insulin requires a carboxypeptidase. Carboxypeptidases also function in blood clotting, growth factor production, wound healing, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Factor XII
Coagulation factor XII, also known as Hageman factor, is a plasma protein involved in coagulation. 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 ''F12'' gene. Genetics The gene for factor XII is located on the tip of the long arm of the fifth chromosome (5q33-qter). 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 in molecular weight. The 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, while the light chain contains the protease domain. FXII can be cleaved sequentially at two sites, Arg353 and Arg334, with the second cleavage liberating the light chain and forming β-FXIIa. The structure of the FnI-EGF-like tandem domain ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prekallikrein
Prekallikrein (PK), also known as Fletcher factor, is an 85,000 Mr serine protease that complexes with high-molecular-weight kininogen. PK is the precursor of plasma kallikrein, which is a serine protease that activates kinins. PK is cleaved to produce kallikrein by activated Factor XII (Hageman factor). Structure Prekallikrein is homologous to factor XI, and similarly consists of four apple domains and a fifth, catalytic serine protease domain. The four apple domains create a disk-like platform around the base of the catalytic domain. However, unlike factor XI, prekallikrein does not form dimers. Prekallikrein is activated to form kallikrein 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 f ... by factor XII cleavage of a bond homologous to the corresponding bond cleaved dur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vasoactivity
A vasoactive substance is an endogenous agent or pharmaceutical drug that has the effect of either increasing or decreasing blood pressure and/or heart rate through its vasoactivity, that is, vascular activity (effect on blood vessels). By adjusting vascular compliance and vascular resistance, typically through vasodilation and vasoconstriction, it helps the body's homeostatic mechanisms (such as the renin–angiotensin system) to keep hemodynamics under control. For example, angiotensin, bradykinin, histamine, nitric oxide, and vasoactive intestinal peptide are important endogenous vasoactive substances. Vasoactive drug therapy is typically used when a patient has the blood pressure and heart rate monitored constantly. The dosage is typically titrated (adjusted up or down) to achieve a desired effect or range of values as determined by competent clinicians. Vasoactive drugs are typically administered using a volumetric infusion device (IV pump). This category of drugs requi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kininogen
Kininogens are Protein precursor, precursor proteins for Kinin, kinins, biologically active Peptide, polypeptides involved in blood coagulation, vasodilation, smooth muscle contraction, Inflammation, inflammatory regulation, and the regulation of the Circulatory system, cardiovascular and Kidney, renal systems. Types of kininogen There are two main types of kininogen (KNG), High-molecular-weight kininogen, high-molecular-weight-kininogen and Low-molecular-weight kininogen, 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 (biochemistry), 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Serine Protease
Serine proteases (or serine endopeptidases) are enzymes that cleave peptide bonds in proteins. Serine serves as the nucleophilic amino acid at the (enzyme's) active site. They are found ubiquitously in both eukaryotes and prokaryotes. Serine proteases fall into two broad categories based on their structure: chymotrypsin-like (trypsin-like) or subtilisin-like. Classification The MEROPS protease classification system counts 16 protein superfamily, superfamilies (as of 2013) each containing many protein family, families. Each superfamily uses the catalytic triad or dyad in a different protein fold and so represent convergent evolution of the catalytic mechanism. The majority belong to the S1 family of the PA clan (superfamily) of proteases. For protein superfamily, superfamilies, P: superfamily, containing a mixture of nucleophile class families, S: purely serine proteases. superfamily. Within each superfamily, protein family, families are designated by their catalytic nucl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kallikrein
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 Chromosome 19 (human), 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 καλλίκρεας (''kallíkreas'') 'pancreas'. Since then, similar enzymes have been found in the biological fluids of humans and other mammals, as we ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
