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, 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 Inhibitor, Kunitz Soybean
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.
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.
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)
Trypsinogen
The inactive proenzyme of trypsin secreted by the pancreas, activated in the duodenum via cleavage by enteropeptidase. (Stedman, 25th ed)
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.
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.
Peptide Fragments
Partial proteins formed by partial hydrolysis of complete proteins or generated through PROTEIN ENGINEERING techniques.
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.
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.
Protease Inhibitors
Compounds which inhibit or antagonize biosynthesis or actions of proteases (ENDOPEPTIDASES).
Cattle
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.
Endopeptidases
Benzoylarginine Nitroanilide
A chromogenic substrate that permits direct measurement of peptide hydrolase activity, e.g., papain and trypsin, by colorimetry. The substrate liberates p-nitroaniline as a chromogenic product.
Serine Proteinase Inhibitors
Exogenous or endogenous compounds which inhibit SERINE ENDOPEPTIDASES.
Serine Endopeptidases
Any member of the group of ENDOPEPTIDASES containing at the active site a serine residue involved in catalysis.
Binding Sites
Benzamidines
Amino Acids
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).
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.
Chromatography, Gel
Pronase
A proteolytic enzyme obtained from Streptomyces griseus.
Thermolysin
Hydrogen-Ion Concentration
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.
Papain
A proteolytic enzyme obtained from Carica papaya. It is also the name used for a purified mixture of papain and CHYMOPAPAIN that is used as a topical enzymatic debriding agent. EC 3.4.22.2.
Cyanogen Bromide
Ovomucin
A heterogeneous mixture of glycoproteins responsible for the gel structure of egg white. It has trypsin-inhibiting activity.
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.
Chromatography, High Pressure Liquid
Peptide Mapping
Analysis of PEPTIDES that are generated from the digestion or fragmentation of a protein or mixture of PROTEINS, by ELECTROPHORESIS; CHROMATOGRAPHY; or MASS SPECTROMETRY. The resulting peptide fingerprints are analyzed for a variety of purposes including the identification of the proteins in a sample, GENETIC POLYMORPHISMS, patterns of gene expression, and patterns diagnostic for diseases.
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.
Streptomyces griseus
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.
Disulfides
Pancreatic Juice
The fluid containing digestive enzymes secreted by the pancreas in response to food in the duodenum.
Plant Proteins
Amylases
Tosylarginine Methyl Ester
alpha 1-Antitrypsin
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).
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.
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.
Carboxypeptidases
Glycoproteins
Conjugated protein-carbohydrate compounds including mucins, mucoid, and amyloid glycoproteins.
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.
Substrate Specificity
Macromolecular Substances
Compounds and molecular complexes that consist of very large numbers of atoms and are generally over 500 kDa in size. In biological systems macromolecular substances usually can be visualized using ELECTRON MICROSCOPY and are distinguished from ORGANELLES by the lack of a membrane structure.
Chemistry
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).
Chemical Phenomena
Hot Temperature
Presence of warmth or heat or a temperature notably higher than an accustomed norm.
Models, Molecular
Enzymes, Immobilized
Cell Membrane
Chymotrypsinogen
Chymotrypsinogen is a zymogen, specifically an inactive precursor form of the enzyme chymotrypsin, which is produced in the pancreas and activated in the small intestine to help digest proteins by cleaving specific peptide bonds.
Intestinal Secretions
Chromatography, Affinity
Rabbits
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.
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.
Soybeans
An annual legume. The SEEDS of this plant are edible and used to produce a variety of SOY FOODS.
Seeds
Microbial Collagenase
A metalloproteinase which degrades helical regions of native collagen to small fragments. Preferred cleavage is -Gly in the sequence -Pro-Xaa-Gly-Pro-. Six forms (or 2 classes) have been isolated from Clostridium histolyticum that are immunologically cross-reactive but possess different sequences and different specificities. Other variants have been isolated from Bacillus cereus, Empedobacter collagenolyticum, Pseudomonas marinoglutinosa, and species of Vibrio and Streptomyces. EC 3.4.24.3.
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.
Escherichia coli
A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.
Oligopeptides
Peptides composed of between two and twelve amino acids.
Chromatography, Ion Exchange
Receptor, PAR-1
A thrombin receptor subtype that couples to HETEROTRIMERIC GTP-BINDING PROTEINS resulting in the activation of a variety of signaling mechanisms including decreased intracellular CYCLIC AMP, increased TYPE C PHOSPHOLIPASES and increased PHOSPHOLIPASE A2.
Structure-Activity Relationship
Enzyme Activation
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.