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Kallidin
Kallidin belongs to the family kinins, which are the peptide hormones. Kallidin is a decapeptide whose sequence is H-Lys-Arg-Pro-Pro-Gly-Phe-Ser-Pro-Phe-Arg-OH. It can be converted to bradykinin by the aminopeptidase enzyme. Effects of Kinins Kallidin is a bioactive kinin peptide formed in response to injury from kininogen precursors through the action of kallikreins. Like all kinins, kallidin, the deca-peptide, plays an important role in several body pathologies. Kinins can regulate the blood pressure by increasing the level of vasopressor substances. They can also bind to the B1 and B2 cell surface receptors, which are G-protein coupled receptors. The mediation of the B1 receptors by des-Arg kinins as agonists can be expressed in several medical issues, such as cancer and trauma. By binding to the B2 receptors, kinins, endogenous agonists, can regulate the vasodilatation and bronchioconstriction. Chemical Mechanisms Since kinins are peptides, they can be cleaved by the p ... [...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] |
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] |
Bradykinin Receptor
The bradykinin receptor family is a group of G-protein coupled receptors whose principal ligand is the protein bradykinin. There are two Bradykinin receptors: the B1 receptor and the B2 receptor. B1 receptor Bradykinin receptor B1 (B1) is a G-protein coupled receptor encoded by the BDKRB1 gene in humans. Its principal ligand is bradykinin, a 9 amino acid peptide generated in pathophysiologic conditions such as inflammation, trauma, burns, shock, and allergy. The B1 receptor is one of two G protein-coupled receptors that have been found which bind bradykinin and mediate responses to these pathophysiologic conditions. B1 protein is synthesized by de novo following tissue injury and receptor binding leads to an increase in the cytosolic calcium ion concentration, ultimately resulting in chronic and acute inflammatory responses. B2 receptor The B2 receptor is a G protein-coupled receptor, coupled to Gq and Gi. Gq stimulates phospholipase C to increase intracellular free cal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bronchoconstriction
Bronchoconstriction is the constriction of the airways in the lungs due to the tightening of surrounding smooth muscle, with consequent coughing, wheezing, and shortness of breath. Causes The condition has a number of causes, the most common being emphysema as well as asthma. Exercise and allergies can bring on the symptoms in an otherwise asymptomatic individual. Emphysema With emphysema the shortness of breath due to effective bronchoconstriction from excessive very thick mucus blockage (it is so thick that great difficulty is encountered in expelling it resulting in near exhaustion at times) can bring on panic attacks unless the individual expects this and has effectively learned pursed lip breathing to more quickly transfer oxygen to the blood via the damaged alveoli resulting from the disease. The most common cause of emphysema is smoking and smoking cessation is mandatory if this incurable disease is to be treated. Prevention of bronchoconstriction by this pathway is vit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Peptides
Peptides are short chains of amino acids linked by peptide bonds. A polypeptide is a longer, continuous, unbranched peptide chain. Polypeptides that have a molecular mass of 10,000 Dalton (unit), Da or more are called proteins. Chains of fewer than twenty amino acids are called oligopeptides, and include dipeptides, tripeptides, and tetrapeptides. Peptides fall under the broad chemical classes of biopolymer, biological polymers and oligomers, alongside nucleic acids, oligosaccharides, polysaccharides, and others. Proteins consist of one or more polypeptides arranged in a biologically functional way, often bound to ligand (biochemistry), ligands such as coenzymes and cofactor (biochemistry), cofactors, to another protein or other macromolecule such as DNA or RNA, or to complex macromolecular assemblies. Amino acids that have been incorporated into peptides are termed Residue (chemistry)#Biochemistry, residues. A water molecule is released during formation of each amide bond.. Al ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bradykinin
Bradykinin (BK) (from Greek ''brady-'' 'slow' + ''-kinin'', ''kīn(eîn)'' 'to move') is a peptide that promotes inflammation. It causes arterioles to dilate (enlarge) via the release of prostacyclin, nitric oxide, and endothelium-derived hyperpolarizing factor and makes veins constrict, via prostaglandin F2, thereby leading to leakage into capillary beds, due to the increased pressure in the capillaries. Bradykinin consists of nine amino acids, and is a physiologically and pharmacologically active peptide of the kinin group of proteins. A class of drugs called angiotensin-converting-enzyme inhibitors (ACE inhibitors) increase bradykinin levels by inhibiting its degradation, thereby increasing its blood pressure lowering effect. ACE inhibitors are FDA approved for the treatment of hypertension and heart failure. Structure Bradykinin, sometimes referred to as BK, is a 9–amino acid Translation (genetics), peptide chain. The amino acid sequence of bradykinin is: arginine, Arg-pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
High-performance Liquid Chromatography
High-performance liquid chromatography (HPLC), formerly referred to as high-pressure liquid chromatography, is a technique in analytical chemistry used to separate, identify, and quantify specific components in mixtures. The mixtures can originate from food, chemicals, pharmaceuticals, biological, environmental and agriculture, etc., which have been dissolved into liquid solutions. It relies on high pressure pumps, which deliver mixtures of various solvents, called the mobile phase, which flows through the system, collecting the sample mixture on the way, delivering it into a cylinder, called the column, filled with solid particles, made of adsorbent material, called the stationary phase. Each component in the sample interacts differently with the adsorbent material, causing different migration rates for each component. These different rates lead to separation as the species flow out of the column into a specific detector such as UV detectors. The output of the detecto ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radioimmunoassay
A radioimmunoassay (RIA) is an immunoassay that uses radioactive tracer, radiolabeled molecules in a stepwise formation of immune complexes. A RIA is a very sensitive in vitro assay technique used to measure concentrations of substances, usually measuring antigen concentrations (for example, hormone levels in blood) by use of antibody, antibodies. The RIA technique is extremely sensitivity (tests), sensitive and extremely Specificity (tests), specific, and although it requires specialized equipment, it remains among the least expensive methods to perform such measurements. It requires special precautions and licensing, since radioactive substances are used. In contrast, an immunoradiometric assay (IRMA) is an immunoassay that uses radiolabeled molecules but in an immediate rather than stepwise way. A radioallergosorbent test (RAST) is an example of radioimmunoassay. It is used to detect the causative allergen for an allergy. Method Classically, to perform a radioimmunoassay, a k ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
N-terminal
The N-terminus (also known as the amino-terminus, NH2-terminus, N-terminal end or amine-terminus) is the start of a protein or polypeptide, referring to the free amine group (-NH2) located at the end of a polypeptide. Within a peptide, the amine group is bonded to the carboxylic group of another amino acid, making it a chain. That leaves a free carboxylic group at one end of the peptide, called the C-terminus, and a free amine group on the other end called the N-terminus. By convention, peptide sequences are written N-terminus to C-terminus, left to right (in LTR writing systems). This correlates the translation direction to the text direction, because when a protein is translated from messenger RNA, it is created from the N-terminus to the C-terminus, as amino acids are added to the carboxyl end of the protein. Chemistry Each amino acid has an amine group and a carboxylic group. Amino acids link to one another by peptide bonds which form through a dehydration reaction that j ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lysine
Lysine (symbol Lys or K) is an α-amino acid that is a precursor to many proteins. Lysine contains an α-amino group (which is in the protonated form when the lysine is dissolved in water at physiological pH), an α-carboxylic acid group (which is in the deprotonated form when the lysine is dissolved in water at physiological pH), and a side chain (which is partially protonated when the lysine is dissolved in water at physiological pH), and so it is classified as a basic, charged (in water at physiological pH), aliphatic amino acid. It is encoded by the codons AAA and AAG. Like almost all other amino acids, the α-carbon is chiral and lysine may refer to either enantiomer or a racemic mixture of both. For the purpose of this article, lysine will refer to the biologically active enantiomer L-lysine, where the α-carbon is in the ''S'' configuration. The human body cannot synthesize lysine. It is essential in humans and must therefore be obtained from the diet. In orga ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Peptidases
A protease (also called a peptidase, proteinase, or proteolytic enzyme) is an enzyme that catalyzes proteolysis, breaking down proteins into smaller polypeptides or single amino acids, and spurring the formation of new protein products. They do this by cleaving the peptide bonds within proteins by hydrolysis, a reaction where water breaks bonds. Proteases are involved in numerous biological pathways, including digestion of ingested proteins, protein catabolism (breakdown of old proteins), and cell signaling. In the absence of functional accelerants, proteolysis would be very slow, taking hundreds of years. Proteases can be found in all forms of life and viruses. They have independently evolved multiple times, and different classes of protease can perform the same reaction by completely different catalytic mechanisms. Classification Based on catalytic residue Proteases can be classified into seven broad groups: * Serine proteases - using a serine alcohol * Cysteine proteases ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kinin
A kinin is any of various structurally related peptides, 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; the name was changed to avoid confusion. Effects of kinins Kinins 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. Kinins act on axons to block nerve impulses, which leads to distal muscle relaxation. They are also potent nerve stimulators which are mostly responsible for the pain sensation (and sometimes itching). Kinins increase vasc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
