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Trypsin Inhibitors: Serine proteinase inhibitors which inhibit trypsin. They may be endogenous or exogenous compounds.Trypsin Inhibitor, Kazal Pancreatic: A pancreatic trypsin inhibitor common to all mammals. It is secreted with the zymogens into the pancreatic juice. It is a protein composed of 56 amino acid residues and is different in amino acid composition and physiological activity from the Kunitz bovine pancreatic trypsin inhibitor (APROTININ).Trypsin: A serine endopeptidase that is formed from TRYPSINOGEN in the pancreas. It is converted into its active form by ENTEROPEPTIDASE in the small intestine. It catalyzes hydrolysis of the carboxyl group of either arginine or lysine. EC 3.4.21.4.Trypsin Inhibitor, Kunitz Soybean: A high-molecular-weight protein (approximately 22,500) containing 198 amino acid residues. It is a strong inhibitor of trypsin and human plasmin.Aprotinin: A single-chain polypeptide derived from bovine tissues consisting of 58 amino-acid residues. It is an inhibitor of proteolytic enzymes including CHYMOTRYPSIN; KALLIKREIN; PLASMIN; and TRYPSIN. It is used in the treatment of HEMORRHAGE associated with raised plasma concentrations of plasmin. It is also used to reduce blood loss and transfusion requirements in patients at high risk of major blood loss during and following open heart surgery with EXTRACORPOREAL CIRCULATION. (Reynolds JEF(Ed): Martindale: The Extra Pharmacopoeia (electronic version). Micromedex, Inc, Englewood, CO, 1995)Trypsin Inhibitor, Bowman-Birk Soybean: A low-molecular-weight protein (minimum molecular weight 8000) which has the ability to inhibit trypsin as well as chymotrypsin at independent binding sites. It is characterized by a high cystine content and the absence of glycine.Chymotrypsin: A serine endopeptidase secreted by the pancreas as its zymogen, CHYMOTRYPSINOGEN and carried in the pancreatic juice to the duodenum where it is activated by TRYPSIN. It selectively cleaves aromatic amino acids on the carboxyl side.Trypsinogen: The inactive proenzyme of trypsin secreted by the pancreas, activated in the duodenum via cleavage by enteropeptidase. (Stedman, 25th ed)Protease Inhibitors: Compounds which inhibit or antagonize biosynthesis or actions of proteases (ENDOPEPTIDASES).Amino Acid Sequence: The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.Serine Proteinase Inhibitors: Exogenous or endogenous compounds which inhibit SERINE ENDOPEPTIDASES.Plant Proteins: Proteins found in plants (flowers, herbs, shrubs, trees, etc.). The concept does not include proteins found in vegetables for which VEGETABLE PROTEINS is available.Soybeans: An annual legume. The SEEDS of this plant are edible and used to produce a variety of SOY FOODS.Gabexate: A serine proteinase inhibitor used therapeutically in the treatment of pancreatitis, disseminated intravascular coagulation (DIC), and as a regional anticoagulant for hemodialysis. The drug inhibits the hydrolytic effects of thrombin, plasmin, and kallikrein, but not of chymotrypsin and aprotinin.Molecular Sequence Data: Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.Cattle: Domesticated bovine animals of the genus Bos, usually kept on a farm or ranch and used for the production of meat or dairy products or for heavy labor.Pancreas: A nodular organ in the ABDOMEN that contains a mixture of ENDOCRINE GLANDS and EXOCRINE GLANDS. The small endocrine portion consists of the ISLETS OF LANGERHANS secreting a number of hormones into the blood stream. The large exocrine portion (EXOCRINE PANCREAS) is a compound acinar gland that secretes several digestive enzymes into the pancreatic ductal system that empties into the DUODENUM.Seeds: The encapsulated embryos of flowering plants. They are used as is or for animal feed because of the high content of concentrated nutrients like starches, proteins, and fats. Rapeseed, cottonseed, and sunflower seed are also produced for the oils (fats) they yield.Benzamidines: Amidines substituted with a benzene group. Benzamidine and its derivatives are known as peptidase inhibitors.Peptide Hydrolases: Hydrolases that specifically cleave the peptide bonds found in PROTEINS and PEPTIDES. Examples of sub-subclasses for this group include EXOPEPTIDASES and ENDOPEPTIDASES.Serine Endopeptidases: Any member of the group of ENDOPEPTIDASES containing at the active site a serine residue involved in catalysis.Kallikreins: Proteolytic enzymes from the serine endopeptidase family found in normal blood and urine. Specifically, Kallikreins are potent vasodilators and hypotensives and increase vascular permeability and affect smooth muscle. They act as infertility agents in men. Three forms are recognized, PLASMA KALLIKREIN (EC 3.4.21.34), TISSUE KALLIKREIN (EC 3.4.21.35), and PROSTATE-SPECIFIC ANTIGEN (EC 3.4.21.77).Cucurbitaceae: The gourd plant family of the order Violales, subclass Dilleniidae, class Magnoliopsida. It is sometimes placed in its own order, Cucurbitales. 'Melon' generally refers to CUCUMIS; CITRULLUS; or MOMORDICA.Acacia: A plant genus of the family FABACEAE. The gums and tanning agents obtained from Acacia are called GUM ARABIC. The common name of catechu is more often used for Areca catechu (ARECA).Molecular Weight: The sum of the weight of all the atoms in a molecule.Ovomucin: A heterogeneous mixture of glycoproteins responsible for the gel structure of egg white. It has trypsin-inhibiting activity.Disulfides: Chemical groups containing the covalent disulfide bonds -S-S-. The sulfur atoms can be bound to inorganic or organic moieties.Enteropeptidase: A specialized proteolytic enzyme secreted by intestinal cells. It converts TRYPSINOGEN into its active form TRYPSIN by removing the N-terminal peptide. EC 3.4.21.9.alpha-Amylases: Enzymes that catalyze the endohydrolysis of 1,4-alpha-glycosidic linkages in STARCH; GLYCOGEN; and related POLYSACCHARIDES and OLIGOSACCHARIDES containing 3 or more 1,4-alpha-linked D-glucose units.Amino Acids: Organic compounds that generally contain an amino (-NH2) and a carboxyl (-COOH) group. Twenty alpha-amino acids are the subunits which are polymerized to form proteins.Endopeptidases: A subclass of PEPTIDE HYDROLASES that catalyze the internal cleavage of PEPTIDES or PROTEINS.Acrosin: A trypsin-like enzyme of spermatozoa which is not inhibited by alpha 1 antitrypsin.Protein Conformation: The characteristic 3-dimensional shape of a protein, including the secondary, supersecondary (motifs), tertiary (domains) and quaternary structure of the peptide chain. PROTEIN STRUCTURE, QUATERNARY describes the conformation assumed by multimeric proteins (aggregates of more than one polypeptide chain).Kinetics: The rate dynamics in chemical or physical systems.Fibrinolysin: A product of the lysis of plasminogen (profibrinolysin) by PLASMINOGEN activators. It is composed of two polypeptide chains, light (B) and heavy (A), with a molecular weight of 75,000. It is the major proteolytic enzyme involved in blood clot retraction or the lysis of fibrin and quickly inactivated by antiplasmins.Fagopyrum: A plant genus of the family POLYGONACEAE that is used as an EDIBLE GRAIN. Although the seeds are used as cereal, the plant is not one of the cereal grasses (POACEAE).Glycoproteins: Conjugated protein-carbohydrate compounds including mucins, mucoid, and amyloid glycoproteins.Pancreatic Elastase: A protease of broad specificity, obtained from dried pancreas. Molecular weight is approximately 25,000. The enzyme breaks down elastin, the specific protein of elastic fibers, and digests other proteins such as fibrin, hemoglobin, and albumin. EC 3.4.21.36.Hydrogen-Ion Concentration: The normality of a solution with respect to HYDROGEN ions; H+. It is related to acidity measurements in most cases by pH = log 1/2[1/(H+)], where (H+) is the hydrogen ion concentration in gram equivalents per liter of solution. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)Pancreatic Juice: The fluid containing digestive enzymes secreted by the pancreas in response to food in the duodenum.Erythrina: A genus of leguminous shrubs or trees, mainly tropical, yielding useful compounds such as ALKALOIDS and PLANT LECTINS.Cholecystokinin: A peptide, of about 33 amino acids, secreted by the upper INTESTINAL MUCOSA and also found in the central nervous system. It causes gallbladder contraction, release of pancreatic exocrine (or digestive) enzymes, and affects other gastrointestinal functions. Cholecystokinin may be the mediator of satiety.Binding Sites: The parts of a macromolecule that directly participate in its specific combination with another molecule.Amylases: A group of amylolytic enzymes that cleave starch, glycogen, and related alpha-1,4-glucans. (Stedman, 25th ed) EC 3.2.1.-.Peptide Fragments: Partial proteins formed by partial hydrolysis of complete proteins or generated through PROTEIN ENGINEERING techniques.Receptor, PAR-2: A G-protein-coupled, proteinase-activated receptor that is expressed in a variety of tissues including ENDOTHELIUM; LEUKOCYTES; and the GASTROINTESTINAL TRACT. The receptor is activated by TRYPSIN, which cleaves off the N-terminal peptide from the receptor. The new N-terminal peptide is a cryptic ligand for the receptor. The uncleaved receptor can also be activated by the N-terminal peptide present on the activated THROMBIN RECEPTOR and by small synthetic peptides that contain the unmasked N-terminal sequence.Fabaceae: The large family of plants characterized by pods. Some are edible and some cause LATHYRISM or FAVISM and other forms of poisoning. Other species yield useful materials like gums from ACACIA and various LECTINS like PHYTOHEMAGGLUTININS from PHASEOLUS. Many of them harbor NITROGEN FIXATION bacteria on their roots. Many but not all species of "beans" belong to this family.Thermolysin: A thermostable extracellular metalloendopeptidase containing four calcium ions. (Enzyme Nomenclature, 1992) 3.4.24.27.Chromatography, Gel: Chromatography on non-ionic gels without regard to the mechanism of solute discrimination.Models, Molecular: Models used experimentally or theoretically to study molecular shape, electronic properties, or interactions; includes analogous molecules, computer-generated graphics, and mechanical structures.Hydrolysis: The process of cleaving a chemical compound by the addition of a molecule of water.Allylglycine: An inhibitor of glutamate decarboxylase and an antagonist of GAMMA-AMINOBUTYRIC ACID. It is used to induce convulsions in experimental animals.Chromatography, High Pressure Liquid: Liquid chromatographic techniques which feature high inlet pressures, high sensitivity, and high speed.Streptomyces griseus: An actinomycete from which the antibiotics STREPTOMYCIN, grisein, and CANDICIDIN are obtained.Isoflurophate: A di-isopropyl-fluorophosphate which is an irreversible cholinesterase inhibitor used to investigate the NERVOUS SYSTEM.Plants, Medicinal: Plants whose roots, leaves, seeds, bark, or other constituent parts possess therapeutic, tonic, purgative, curative or other pharmacologic attributes, when administered to man or animals.alpha 1-Antitrypsin: Plasma glycoprotein member of the serpin superfamily which inhibits TRYPSIN; NEUTROPHIL ELASTASE; and other PROTEOLYTIC ENZYMES.alpha-Macroglobulins: Glycoproteins with a molecular weight of approximately 620,000 to 680,000. Precipitation by electrophoresis is in the alpha region. They include alpha 1-macroglobulins and alpha 2-macroglobulins. These proteins exhibit trypsin-, chymotrypsin-, thrombin-, and plasmin-binding activity and function as hormonal transporters.Pancreatitis: INFLAMMATION of the PANCREAS. Pancreatitis is classified as acute unless there are computed tomographic or endoscopic retrograde cholangiopancreatographic findings of CHRONIC PANCREATITIS (International Symposium on Acute Pancreatitis, Atlanta, 1992). The two most common forms of acute pancreatitis are ALCOHOLIC PANCREATITIS and gallstone pancreatitis.Pancreatitis, Chronic: INFLAMMATION of the PANCREAS that is characterized by recurring or persistent ABDOMINAL PAIN with or without STEATORRHEA or DIABETES MELLITUS. It is characterized by the irregular destruction of the pancreatic parenchyma which may be focal, segmental, or diffuse.Prekallikrein: A plasma protein which is the precursor of kallikrein. Plasma that is deficient in prekallikrein has been found to be abnormal in thromboplastin formation, kinin generation, evolution of a permeability globulin, and plasmin formation. The absence of prekallikrein in plasma leads to Fletcher factor deficiency, a congenital disease.Magnetic Resonance Spectroscopy: Spectroscopic method of measuring the magnetic moment of elementary particles such as atomic nuclei, protons or electrons. It is employed in clinical applications such as NMR Tomography (MAGNETIC RESONANCE IMAGING).Electrophoresis, Polyacrylamide Gel: Electrophoresis in which a polyacrylamide gel is used as the diffusion medium.Protein Folding: Processes involved in the formation of TERTIARY PROTEIN STRUCTURE.Kinins: A generic term used to describe a group of polypeptides with related chemical structures and pharmacological properties that are widely distributed in nature. These peptides are AUTACOIDS that act locally to produce pain, vasodilatation, increased vascular permeability, and the synthesis of prostaglandins. Thus, they comprise a subset of the large number of mediators that contribute to the inflammatory response. (From Goodman and Gilman's The Pharmacologic Basis of Therapeutics, 8th ed, p588)Sequence Homology, Amino Acid: The degree of similarity between sequences of amino acids. This information is useful for the analyzing genetic relatedness of proteins and species.Carboxypeptidases: Enzymes that act at a free C-terminus of a polypeptide to liberate a single amino acid residue.Factor XII: Stable blood coagulation factor activated by contact with the subendothelial surface of an injured vessel. Along with prekallikrein, it serves as the contact factor that initiates the intrinsic pathway of blood coagulation. Kallikrein activates factor XII to XIIa. Deficiency of factor XII, also called the Hageman trait, leads to increased incidence of thromboembolic disease. Mutations in the gene for factor XII that appear to increase factor XII amidolytic activity are associated with HEREDITARY ANGIOEDEMA TYPE III.Plants: Multicellular, eukaryotic life forms of kingdom Plantae (sensu lato), comprising the VIRIDIPLANTAE; RHODOPHYTA; and GLAUCOPHYTA; all of which acquired chloroplasts by direct endosymbiosis of CYANOBACTERIA. They are characterized by a mainly photosynthetic mode of nutrition; essentially unlimited growth at localized regions of cell divisions (MERISTEMS); cellulose within cells providing rigidity; the absence of organs of locomotion; absence of nervous and sensory systems; and an alternation of haploid and diploid generations.Carboxypeptidases A: Carboxypeptidases that are primarily found the DIGESTIVE SYSTEM that catalyze the release of C-terminal amino acids. Carboxypeptidases A have little or no activity for hydrolysis of C-terminal ASPARTIC ACID; GLUTAMIC ACID; ARGININE; LYSINE; or PROLINE. This enzyme requires ZINC as a cofactor and was formerly listed as EC 3.4.2.1 and EC 3.4.12.2.Factor XIIa: Activated form of factor XII. In the initial event in the intrinsic pathway of blood coagulation, kallikrein (with cofactor HIGH MOLECULAR WEIGHT KININOGEN) cleaves factor XII to XIIa. Factor XIIa is then further cleaved by kallikrein, plasmin, and trypsin to yield smaller factor XII fragments (Hageman-Factor fragments). These fragments increase the activity of prekallikrein to kallikrein but decrease the procoagulant activity of factor XII.Chymases: A family of neutral serine proteases with CHYMOTRYPSIN-like activity. Chymases are primarily found in the SECRETORY GRANULES of MAST CELLS and are released during mast cell degranulation.Chromatography, Ion Exchange: Separation technique in which the stationary phase consists of ion exchange resins. The resins contain loosely held small ions that easily exchange places with other small ions of like charge present in solutions washed over the resins.Macroglobulins: Serum globulins with high molecular weight. (Dorland, 28th ed)Peptides: Members of the class of compounds composed of AMINO ACIDS joined together by peptide bonds between adjacent amino acids into linear, branched or cyclical structures. OLIGOPEPTIDES are composed of approximately 2-12 amino acids. Polypeptides are composed of approximately 13 or more amino acids. PROTEINS are linear polypeptides that are normally synthesized on RIBOSOMES.Momordica: A plant genus of the family CUCURBITACEAE. It is a source of momordin.Veronica: A plant genus of the family Plantaginaceae. Members contain bis-sesquiterpene and iridoid glucosides.Hot Temperature: Presence of warmth or heat or a temperature notably higher than an accustomed norm.Substrate Specificity: A characteristic feature of enzyme activity in relation to the kind of substrate on which the enzyme or catalytic molecule reacts.HomoarginineLysine Carboxypeptidase: A metallocarboxypeptidase that removes C-terminal basic amino acid from peptides and proteins, with preference shown for lysine over arginine. It is a plasma zinc enzyme that inactivates bradykinin and anaphylatoxins.Isoelectric Focusing: Electrophoresis in which a pH gradient is established in a gel medium and proteins migrate until they reach the site (or focus) at which the pH is equal to their isoelectric point.Carboxypeptidase B: A ZINC-dependent carboxypeptidase primary found in the DIGESTIVE SYSTEM. The enzyme catalyzes the preferential cleavage of a C-terminal peptidyl-L-lysine or arginine. It was formerly classified as EC 3.4.2.2 and EC 3.4.12.3.Hemolymph: The blood/lymphlike nutrient fluid of some invertebrates.Protein Binding: The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.Intestinal Secretions: Fluids originating from the epithelial lining of the intestines, adjoining exocrine glands and from organs such as the liver, which empty into the cavity of the intestines.Swine: Any of various animals that constitute the family Suidae and comprise stout-bodied, short-legged omnivorous mammals with thick skin, usually covered with coarse bristles, a rather long mobile snout, and small tail. Included are the genera Babyrousa, Phacochoerus (wart hogs), and Sus, the latter containing the domestic pig (see SUS SCROFA).Tryptases: A family of neutral serine proteases with TRYPSIN-like activity. Tryptases are primarily found in the SECRETORY GRANULES of MAST CELLS and are released during mast cell degranulation.Proteins: Linear POLYPEPTIDES that are synthesized on RIBOSOMES and may be further modified, crosslinked, cleaved, or assembled into complex proteins with several subunits. The specific sequence of AMINO ACIDS determines the shape the polypeptide will take, during PROTEIN FOLDING, and the function of the protein.Ascaris: A genus of nematodes of the superfamily ASCARIDOIDEA whose species usually inhabit the intestine.Guanidines: A family of iminourea derivatives. The parent compound has been isolated from mushrooms, corn germ, rice hulls, mussels, earthworms, and turnip juice. Derivatives may have antiviral and antifungal properties.Momordica charantia: A plant species of the family CUCURBITACEAE. It is a source of ribosome-inactivating proteins and triterpene glycosides.Chemistry: A basic science concerned with the composition, structure, and properties of matter; and the reactions that occur between substances and the associated energy exchange.Cystine-Knot Miniproteins: A structurally-related family of small proteins that form a stable tertiary fold pattern which is supported by a series of disulfide bonds. The arrangement of disulfide bonds between the CYSTEINE moieties results in a knotted structure which is unique to this family of proteins.Kininogens: Endogenous peptides present in most body fluids. Certain enzymes convert them to active KININS which are involved in inflammation, blood clotting, complement reactions, etc. Kininogens belong to the cystatin superfamily. They are cysteine proteinase inhibitors. HIGH-MOLECULAR-WEIGHT KININOGEN; (HMWK); is split by plasma kallikrein to produce BRADYKININ. LOW-MOLECULAR-WEIGHT KININOGEN; (LMWK); is split by tissue kallikrein to produce KALLIDIN.Base Sequence: The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.Malate Dehydrogenase (NADP+)Chemical Phenomena: The composition, conformation, and properties of atoms and molecules, and their reaction and interaction processes.Litchi: A plant genus of the family SAPINDACEAE that bears sweet fruits. Unusual fatty acids such as cyclopropanoic fatty acids have been identified in the seeds.Elapid Venoms: Venoms from snakes of the family Elapidae, including cobras, kraits, mambas, coral, tiger, and Australian snakes. The venoms contain polypeptide toxins of various kinds, cytolytic, hemolytic, and neurotoxic factors, but fewer enzymes than viper or crotalid venoms. Many of the toxins have been characterized.Protein Denaturation: Disruption of the non-covalent bonds and/or disulfide bonds responsible for maintaining the three-dimensional shape and activity of the native protein.Recombinant Proteins: Proteins prepared by recombinant DNA technology.Leukocyte Elastase: An enzyme that catalyzes the hydrolysis of proteins, including elastin. It cleaves preferentially bonds at the carboxyl side of Ala and Val, with greater specificity for Ala. EC 3.4.21.37.Chromatography: Techniques used to separate mixtures of substances based on differences in the relative affinities of the substances for mobile and stationary phases. A mobile phase (fluid or gas) passes through a column containing a stationary phase of porous solid or liquid coated on a solid support. Usage is both analytical for small amounts and preparative for bulk amounts.Enzyme Precursors: Physiologically inactive substances that can be converted to active enzymes.Panicum: A plant genus of the family POACEAE. The seed is one of the EDIBLE GRAINS used in millet cereals and in feed for birds and livestock (ANIMAL FEED). It contains diosgenin (SAPONINS).Thrombin: An enzyme formed from PROTHROMBIN that converts FIBRINOGEN to FIBRIN.Ascaridia: A genus of nematode worms in the superfamily Heterakoidea. A. galli and A. lineata are important intestinal parasites of domestic fowl.Temperature: The property of objects that determines the direction of heat flow when they are placed in direct thermal contact. The temperature is the energy of microscopic motions (vibrational and translational) of the particles of atoms.Plants, Edible: An organism of the vegetable kingdom suitable by nature for use as a food, especially by human beings. Not all parts of any given plant are edible but all parts of edible plants have been known to figure as raw or cooked food: leaves, roots, tubers, stems, seeds, buds, fruits, and flowers. The most commonly edible parts of plants are FRUIT, usually sweet, fleshy, and succulent. Most edible plants are commonly cultivated for their nutritional value and are referred to as VEGETABLES.Prostatic Secretory Proteins: Proteins secreted by the prostate gland. The major secretory proteins from the human prostate gland include PROSTATE-SPECIFIC ANTIGEN, prostate-specific acid phosphatase, prostate-specific membrane antigen, and prostate-specific protein-94.Duodenum: The shortest and widest portion of the SMALL INTESTINE adjacent to the PYLORUS of the STOMACH. It is named for having the length equal to about the width of 12 fingers.Pepsin A: Formed from pig pepsinogen by cleavage of one peptide bond. The enzyme is a single polypeptide chain and is inhibited by methyl 2-diaazoacetamidohexanoate. It cleaves peptides preferentially at the carbonyl linkages of phenylalanine or leucine and acts as the principal digestive enzyme of gastric juice.Caseins: A mixture of related phosphoproteins occurring in milk and cheese. The group is characterized as one of the most nutritive milk proteins, containing all of the common amino acids and rich in the essential ones.GlobulinsChromatography, Affinity: A chromatographic technique that utilizes the ability of biological molecules to bind to certain ligands specifically and reversibly. It is used in protein biochemistry. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Thermodynamics: A rigorously mathematical analysis of energy relationships (heat, work, temperature, and equilibrium). It describes systems whose states are determined by thermal parameters, such as temperature, in addition to mechanical and electromagnetic parameters. (From Hawley's Condensed Chemical Dictionary, 12th ed)Seed Storage Proteins: One or more types of plant seed proteins providing the large amounts of AMINO ACIDS utilized in GERMINATION and SEEDLING growth. As seeds are the major food source from AGRICULTURAL CROPS, seed storage proteins are a major source of DIETARY PROTEINS.Murraya: A plant genus of the family RUTACEAE. Members contain murrayanine, koenine, isomahanine, kwangsine, siamenol, murrayafoline A, murrayaquinone A and other cytotoxic carbazolequinones.Cyanogen Bromide: Cyanogen bromide (CNBr). A compound used in molecular biology to digest some proteins and as a coupling reagent for phosphoroamidate or pyrophosphate internucleotide bonds in DNA duplexes.Alpha-Globulins: Serum proteins that have the most rapid migration during ELECTROPHORESIS. This subgroup of globulins is divided into faster and slower alpha(1)- and alpha(2)-globulins.Receptors, Thrombin: A family of proteinase-activated receptors that are specific for THROMBIN. They are found primarily on PLATELETS and on ENDOTHELIAL CELLS. Activation of thrombin receptors occurs through the proteolytic action of THROMBIN, which cleaves the N-terminal peptide from the receptor to reveal a new N-terminal peptide that is a cryptic ligand for the receptor. The receptors signal through HETEROTRIMERIC GTP-BINDING PROTEINS. Small synthetic peptides that contain the unmasked N-terminal peptide sequence can also activate the receptor in the absence of proteolytic activity.