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α2-macroglobulin
α2-Macroglobulin (α2M) or alpha-2-macroglobulin is a large (720 KDa) plasma protein found in the blood. It is mainly produced by the liver, and also locally synthesized by macrophages, fibroblasts, and adrenocortical cells. In humans it is encoded by the ''A2M'' gene. α2-Macroglobulin acts as an antiprotease and is able to inactivate an enormous variety of proteinases. It functions as an inhibitor of fibrinolysis by inhibiting plasmin and kallikrein. It functions as an inhibitor of coagulation by inhibiting thrombin. α2-macroglobulin may act as a carrier protein because it also binds to numerous growth factors and cytokines, such as platelet-derived growth factor, basic fibroblast growth factor, TGF-β, insulin, and IL-1β. No specific deficiency with associated disease has been recognized, and no disease state is attributed to low concentrations of α2-macroglobulin. The concentration of α2-macroglobulin rises 10-fold or more in the nephrotic syndrome when other lower mo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plasmin
Plasmin is an important enzyme () present in blood that degrades many blood plasma proteins, including fibrin thrombus, 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 proteolysis, 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 g ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pregnancy Zone Protein
Pregnancy zone protein (PZP), also known as the pregnancy-associated α2-glycoprotein (α2-PAG or PAα2G), is a protein which in humans is encoded by the ''PZP'' gene on chromosome 12. PZP is part of the alpha-2 globulin family of proteins. It is often associated with pregnancy, during which it can be the most abundant among the plasma proteins.Chiabrando GA, Vides MA, Sanchez MC (2002). “Differential binding properties of human pregnancy zone protein– and a2-macroglobulin–proteinase complexes to low-density lipoprotein receptor-related protein”. ''Archives of Biochemistry and Biophysics.'' 398(1): 73–78. PZP is believed to play a role in immune-regulation during pregnancy, however many aspects of its mechanism, function and structure are yet to be determined.Oh JW, Kim SK, Cho K-C, Kim M-S, Suh CS, Lee JR, Kim KP (2017). “Proteomic analysis of human follicular fluid in poor ovarian responders during in vitro fertilization”.''Proteomics.'' 17(6). Charkoftaki ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plasma Protein
Plasma proteins, sometimes referred to as blood proteins, are proteins present in blood plasma. They perform many different functions, including transport of hormones, vitamins and minerals in activity and functioning of the immune system. Other blood proteins act as enzymes, complement, components, protease inhibitors or kinin precursors. Contrary to popular belief, haemoglobin is not a blood protein, as it is carried within red blood cells, rather than in the blood serum. Serum albumin accounts for 55% of blood proteins, is a major contributor to maintaining the oncotic pressure of plasma and assists, as a carrier, in the transport of lipids and steroid hormones. Globulins make up 38% of blood proteins and transport ions, hormones, and lipids assisting in immune function. Fibrinogen comprises 7% of blood proteins; conversion of fibrinogen to insoluble fibrin is essential for blood clotting. The remainder of the plasma proteins (1%) are regulatory proteins, such as enzymes, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protease Inhibitor (biology)
In biology and biochemistry, protease inhibitors, or antiproteases, are molecules that inhibit the function of proteases (enzymes that aid proteolysis, the breakdown of proteins). Many naturally occurring protease inhibitors are proteins. In medicine, ''protease inhibitor'' is often used interchangeably with alpha 1-antitrypsin (A1AT, which is abbreviated PI for this reason). A1AT is indeed the protease inhibitor most often involved in disease, namely in alpha-1 antitrypsin deficiency. Classification Protease inhibitors may be classified either by the type of protease they inhibit, or by their mechanism of action. In 2004 Rawlings and colleagues introduced a classification of protease inhibitors based on similarities detectable at the level of amino acid sequence. This classification initially identified 48 families of inhibitors that could be grouped into 26 related superfamily (or clans) by their structure. According to the MEROPS database there are now 81 families of inhibito ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Steric
Steric effects arise from the spatial arrangement of atoms. When atoms come close together there is generally a rise in the energy of the molecule. Steric effects are nonbonding interactions that influence the shape ( conformation) and reactivity of ions and molecules. Steric effects complement electronic effects, which dictate the shape and reactivity of molecules. Steric repulsive forces between overlapping electron clouds result in structured groupings of molecules stabilized by the way that opposites attract and like charges repel. Steric hindrance Steric hindrance is a consequence of steric effects. Steric hindrance is the slowing of chemical reactions due to steric bulk. It is usually manifested in ''intermolecular reactions'', whereas discussion of steric effects often focus on ''intramolecular interactions''. Steric hindrance is often exploited to control selectivity, such as slowing unwanted side-reactions. Steric hindrance between adjacent groups can also affect ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protease Inhibitor (biology)
In biology and biochemistry, protease inhibitors, or antiproteases, are molecules that inhibit the function of proteases (enzymes that aid proteolysis, the breakdown of proteins). Many naturally occurring protease inhibitors are proteins. In medicine, ''protease inhibitor'' is often used interchangeably with alpha 1-antitrypsin (A1AT, which is abbreviated PI for this reason). A1AT is indeed the protease inhibitor most often involved in disease, namely in alpha-1 antitrypsin deficiency. Classification Protease inhibitors may be classified either by the type of protease they inhibit, or by their mechanism of action. In 2004 Rawlings and colleagues introduced a classification of protease inhibitors based on similarities detectable at the level of amino acid sequence. This classification initially identified 48 families of inhibitors that could be grouped into 26 related superfamily (or clans) by their structure. According to the MEROPS database there are now 81 families of inhibito ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amine
In chemistry, amines (, ) are organic compounds that contain carbon-nitrogen bonds. Amines are formed when one or more hydrogen atoms in ammonia are replaced by alkyl or aryl groups. The nitrogen atom in an amine possesses a lone pair of electrons. Amines can also exist as hetero cyclic compounds. Aniline is the simplest aromatic amine, consisting of a benzene ring bonded to an amino group. Amines are classified into three types: primary (1°), secondary (2°), and tertiary (3°) amines. Primary amines (1°) contain one alkyl or aryl substituent and have the general formula RNH2. Secondary amines (2°) have two alkyl or aryl groups attached to the nitrogen atom, with the general formula R2NH. Tertiary amines (3°) contain three substituent groups bonded to the nitrogen atom, and are represented by the formula R3N. The functional group present in primary amines is called the amino group. Classification of amines Amines can be classified according to the nature and number o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ester
In chemistry, an ester is a compound derived from an acid (either organic or inorganic) in which the hydrogen atom (H) of at least one acidic hydroxyl group () of that acid is replaced by an organyl group (R). These compounds contain a distinctive functional group. Analogues derived from oxygen replaced by other chalcogens belong to the ester category as well. According to some authors, organyl derivatives of acidic hydrogen of other acids are esters as well (e.g. amides), but not according to the IUPAC. Glycerides are fatty acid esters of glycerol; they are important in biology, being one of the main classes of lipids and comprising the bulk of animal fats and vegetable oils. Lactones are cyclic carboxylic esters; naturally occurring lactones are mainly 5- and 6-membered ring lactones. Lactones contribute to the aroma of fruits, butter, cheese, vegetables like celery and other foods. Esters can be formed from oxoacids (e.g. esters of acetic acid, carbonic acid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thiol
In organic chemistry, a thiol (; ), or thiol derivative, is any organosulfur compound of the form , where R represents an alkyl or other organic substituent. The functional group itself is referred to as either a thiol group or a sulfhydryl group, or a sulfanyl group. Thiols are the sulfur analogue of alcohols (that is, sulfur takes the place of oxygen in the hydroxyl () group of an alcohol), and the word is a blend of "''thio-''" with "alcohol". Many thiols have strong odors resembling that of garlic, cabbage or rotten eggs. Thiols are used as odorants to assist in the detection of natural gas (which in pure form is odorless), and the smell of natural gas is due to the smell of the thiol used as the odorant. Nomenclature Thiols are sometimes referred to as mercaptans () or mercapto compounds, a term introduced in 1832 by William Christopher Zeise and is derived from the Latin ('capturing mercury')''Oxford American Dictionaries'' (Mac OS X Leopard). because the thiolate grou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amino Acids
Amino acids are organic compounds that contain both amino and carboxylic acid functional groups. Although over 500 amino acids exist in nature, by far the most important are the Proteinogenic amino acid, 22 α-amino acids incorporated into proteins. Only these 22 appear in the genetic code of life. Amino acids can be classified according to the locations of the core structural functional groups (Alpha and beta carbon, alpha- , beta- , gamma- (γ-) amino acids, etc.); other categories relate to Chemical polarity, polarity, ionization, and side-chain group type (aliphatic, Open-chain compound, acyclic, aromatic, Chemical polarity, polar, etc.). In the form of proteins, amino-acid ''Residue (chemistry)#Biochemistry, residues'' form the second-largest component (water being the largest) of human muscles and other tissue (biology), tissues. Beyond their role as residues in proteins, amino acids participate in a number of processes such as neurotransmitter transport and biosynthesi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Catalytic
Catalysis () is the increase in reaction rate, rate of a chemical reaction due to an added substance known as a catalyst (). Catalysts are not consumed by the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recycles quickly, very small amounts of catalyst often suffice; mixing, surface area, and temperature are important factors in reaction rate. Catalysts generally react with one or more reactants to form reaction intermediate, intermediates that subsequently give the final reaction product, in the process of regenerating the catalyst. The rate increase occurs because the catalyst allows the reaction to occur by an alternative mechanism which may be much faster than the noncatalyzed mechanism. However the noncatalyzed mechanism does remain possible, so that the total rate (catalyzed plus noncatalyzed) can only increase in the presence of the catalyst and never decrease. Catalysis may be classified as either homogeneous catalysis, homogeneou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protease
A protease (also called a peptidase, proteinase, or proteolytic enzyme) is an enzyme that catalysis, 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 Covalent bond, bonds. Proteases are involved in numerous biological pathways, including Digestion#Protein digestion, 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 convergent evolution, 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
