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Bentiromide Synthesis
Bentiromide is a peptide used as a screening test for exocrine pancreatic insufficiency and to monitor the adequacy of supplemental pancreatic therapy. Bentiromide is not available in the United States or Canada; it was withdrawn in the US in October 1996. on bentiromide. Side effects Headache and gastrointestinal disturbances have been reported in patients taking bentiromide. Mechanism of action Bentiromide is given by mouth as a noninvasive test. It is broken down by the pancreatic enzyme chymotrypsin, yielding p-aminobenzoic acid (PABA). The amount of PABA and its metabolites excreted in the urine is taken as a measure of the chymotrypsin-secreting activity of the pancreas. Chemistry * XLogP=3.201 *H_bond_donor=4 *H_bond_acceptor=5 Synthesis It is synthesized by amide formation between ethyl ''p''-aminobenzoate and ''N''-benzoyl-tyrosine using ''N''-methyl-morpholine and ethyl chlorocarbonate for activation. The resulting L-amide is selectively hydrolyzed by seq ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PubChem
PubChem is a database of chemical molecules and their activities against biological assays. The system is maintained by the National Center for Biotechnology Information (NCBI), a component of the National Library of Medicine, which is part of the United States National Institutes of Health (NIH). PubChem can be accessed for free through a web user interface. Millions of compound structures and descriptive datasets can be freely downloaded via FTP. PubChem contains multiple substance descriptions and small molecules with fewer than 100 atoms and 1,000 bonds. More than 80 database vendors contribute to the growing PubChem database. History PubChem was released in 2004 as a component of the Molecular Libraries Program (MLP) of the NIH. As of November 2015, PubChem contains more than 150 million depositor-provided substance descriptions, 60 million unique chemical structures, and 225 million biological activity test results (from over 1 million assay experiments performed on more t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Peptide
Peptides (, ) are short chains of amino acids linked by peptide bonds. Long chains of amino acids are called proteins. Chains of fewer than twenty amino acids are called oligopeptides, and include dipeptides, tripeptides, and tetrapeptides. A polypeptide is a longer, continuous, unbranched peptide chain. Hence, peptides fall under the broad chemical classes of biological polymers and oligomers, alongside nucleic acids, oligosaccharides, polysaccharides, and others. A polypeptide that contains more than approximately 50 amino acids is known as a protein. Proteins consist of one or more polypeptides arranged in a biologically functional way, often bound to ligands such as coenzymes and cofactors, or 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 residues. A water molecule is released during formation of each amide bond.. All peptides except cyclic pep ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Exocrine
Exocrine glands are glands that secrete substances on to an epithelial surface by way of a duct. Examples of exocrine glands include sweat, salivary, mammary, ceruminous, lacrimal, sebaceous, prostate and mucous. Exocrine glands are one of two types of glands in the human body, the other being endocrine glands, which secrete their products directly into the bloodstream. The liver and pancreas are both exocrine and endocrine glands; they are exocrine glands because they secrete products—bile and pancreatic juice—into the gastrointestinal tract through a series of ducts, and endocrine because they secrete other substances directly into the bloodstream. Exocrine sweat glands are part of the integumentary system; they have eccrine and apocrine types. Classification Structure Exocrine glands contain a glandular portion and a duct portion, the structures of which can be used to classify the gland. * The duct portion may be branched (called compound) or unbranched (called simple) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pancreatic
The pancreas is an Organ (anatomy), organ of the digestive system and endocrine system of vertebrates. In humans, it is located in the abdominal cavity, abdomen behind the stomach and functions as a gland. The pancreas is a mixed or heterocrine gland, i.e. it has both an endocrine and a digestive exocrine function. 99% of the pancreas is exocrine and 1% is endocrine. As an endocrine gland, it functions mostly to regulate blood sugar levels, secreting the hormones insulin, glucagon, somatostatin, and pancreatic polypeptide. As a part of the digestive system, it functions as an exocrine gland secreting pancreatic juice into the duodenum through the pancreatic duct. This juice contains bicarbonate, which neutralizes acid entering the duodenum from the stomach; and digestive enzymes, which break down carbohydrates, proteins, and lipids, fats in food entering the duodenum from the stomach. Inflammation of the pancreas is known as pancreatitis, with common causes including chronic Alc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chymotrypsin
Chymotrypsin (, chymotrypsins A and B, alpha-chymar ophth, avazyme, chymar, chymotest, enzeon, quimar, quimotrase, alpha-chymar, alpha-chymotrypsin A, alpha-chymotrypsin) is a digestive enzyme component of pancreatic juice acting in the duodenum, where it performs proteolysis, the breakdown of proteins and polypeptides. Chymotrypsin preferentially cleaves peptide amide bonds where the side chain of the amino acid N-terminal to the scissile amide bond (the P1 position) is a large hydrophobic amino acid (tyrosine, tryptophan, and phenylalanine). These amino acids contain an aromatic ring in their side chain that fits into a hydrophobic pocket (the S1 position) of the enzyme. It is activated in the presence of trypsin. The hydrophobic and shape complementarity between the peptide substrate P1 side chain and the enzyme S1 binding cavity accounts for the substrate specificity of this enzyme. Chymotrypsin also hydrolyzes other amide bonds in peptides at slower rates, particularly tho ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
P-aminobenzoic Acid
4-Aminobenzoic acid (also known as ''para''-aminobenzoic acid or PABA because the two functional groups are attached to the benzene ring across from one another in the ''para'' position) is an organic compound with the formula H2NC6H4CO2H. PABA is a white solid, although commercial samples can appear gray. It is slightly soluble in water. It consists of a benzene ring substituted with amino and carboxyl groups. The compound occurs extensively in the natural world. Production and occurrence In industry, PABA is prepared mainly by two routes: * Reduction of 4-nitrobenzoic acid * Hoffman degradation of the monoamide derived from terephthalic acid. Food sources of PABA include liver, brewer's yeast (and unfiltered beer), kidney, molasses, mushrooms, and whole grains. A review on this compound. Biology Biochemistry PABA is an intermediate in the synthesis of folate by bacteria, plants, and fungi. Many bacteria, including those found in the human intestinal tract such as ''E ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metabolites
In biochemistry, a metabolite is an intermediate or end product of metabolism. The term is usually used for small molecules. Metabolites have various functions, including fuel, structure, signaling, stimulatory and inhibitory effects on enzymes, catalytic activity of their own (usually as a cofactor to an enzyme), defense, and interactions with other organisms (e.g. pigments, odorants, and pheromones). A primary metabolite is directly involved in normal "growth", development, and reproduction. Ethylene exemplifies a primary metabolite produced large-scale by industrial microbiology. A secondary metabolite is not directly involved in those processes, but usually has an important ecological function. Examples include antibiotics and pigments such as resins and terpenes etc. Some antibiotics use primary metabolites as precursors, such as actinomycin, which is created from the primary metabolite tryptophan. Some sugars are metabolites, such as fructose or glucose, which are both pre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
XLogP
In the physical sciences, a partition coefficient (''P'') or distribution coefficient (''D'') is the ratio of concentrations of a compound in a mixture of two immiscible solvents at equilibrium. This ratio is therefore a comparison of the solubilities of the solute in these two liquids. The partition coefficient generally refers to the concentration ratio of un-ionized species of compound, whereas the distribution coefficient refers to the concentration ratio of all species of the compound (ionized plus un-ionized). In the chemical and pharmaceutical sciences, both phases usually are solvents. Most commonly, one of the solvents is water, while the second is hydrophobic, such as 1-octanol. Hence the partition coefficient measures how hydrophilic ("water-loving") or hydrophobic ("water-fearing") a chemical substance is. Partition coefficients are useful in estimating the distribution of drugs within the body. Hydrophobic drugs with high octanol-water partition coefficients are m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bentiromide Synthesis
Bentiromide is a peptide used as a screening test for exocrine pancreatic insufficiency and to monitor the adequacy of supplemental pancreatic therapy. Bentiromide is not available in the United States or Canada; it was withdrawn in the US in October 1996. on bentiromide. Side effects Headache and gastrointestinal disturbances have been reported in patients taking bentiromide. Mechanism of action Bentiromide is given by mouth as a noninvasive test. It is broken down by the pancreatic enzyme chymotrypsin, yielding p-aminobenzoic acid (PABA). The amount of PABA and its metabolites excreted in the urine is taken as a measure of the chymotrypsin-secreting activity of the pancreas. Chemistry * XLogP=3.201 *H_bond_donor=4 *H_bond_acceptor=5 Synthesis It is synthesized by amide formation between ethyl ''p''-aminobenzoate and ''N''-benzoyl-tyrosine using ''N''-methyl-morpholine and ethyl chlorocarbonate for activation. The resulting L-amide is selectively hydrolyzed by seq ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dimsyl Sodium
Sodium methylsulfinylmethylide (also called NaDMSO or dimsyl sodium) is the sodium salt of the conjugate base of dimethyl sulfoxide. This unusual salt has some uses in organic chemistry as a base and nucleophile. Since the first publication in 1965 by Corey ''et al.'', a number of additional uses for this reagent have been identified. Preparation Sodium methylsulfinylmethylide is prepared by heating sodium hydride or sodium amide in DMSO :CH3SOCH3 + NaH → CH3SOCH2−Na+ + H2 :CH3SOCH3 + NaNH2 → CH3SOCH2−Na+ + NH3 Reactions As a Base The pKa of DMSO is 35, which leads NaDMSO to be a powerful Brønsted base. NaDMSO is used in the generation of phosphorus and sulfur ylides. NaDMSO in DMSO is especially convenient in the generation of dimethyloxosulfonium methylide and dimethylsulfonium methylide. Reaction with esters NaDMSO condenses with esters (1) to form β-ketosulfoxides (2), which can be useful intermediates. Reduction of β-ketosulfoxides with aluminium ama ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NaDMSO
Sodium methylsulfinylmethylide (also called NaDMSO or dimsyl sodium) is the sodium salt of the conjugate base of dimethyl sulfoxide. This unusual salt has some uses in organic chemistry as a base and nucleophile. Since the first publication in 1965 by Corey ''et al.'', a number of additional uses for this reagent have been identified. Preparation Sodium methylsulfinylmethylide is prepared by heating sodium hydride or sodium amide in DMSO :CH3SOCH3 + NaH → CH3SOCH2−Na+ + H2 :CH3SOCH3 + NaNH2 → CH3SOCH2−Na+ + NH3 Reactions As a Base The pKa of DMSO is 35, which leads NaDMSO to be a powerful Brønsted base. NaDMSO is used in the generation of phosphorus and sulfur ylides. NaDMSO in DMSO is especially convenient in the generation of dimethyloxosulfonium methylide and dimethylsulfonium methylide. Reaction with esters NaDMSO condenses with esters (1) to form β-ketosulfoxides (2), which can be useful intermediates. Reduction of β-ketosulfoxides with alumi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chronic Pancreatitis
Chronic pancreatitis is a long-standing inflammation of the pancreas that alters the organ's normal structure and functions. It can present as episodes of acute inflammation in a previously injured pancreas, or as chronic damage with persistent pain or malabsorption. It is a disease process characterized by irreversible damage to the pancreas as distinct from reversible changes in acute pancreatitis. Signs and symptoms * Upper abdominal pain: Upper abdominal pain which increases after drinking or eating, lessens when fasting or sitting and leaning forward. Some people may not suffer pain. * Nausea and vomiting * Steatorrhea: Frequent, oily, foul-smelling bowel movements. Damage to the pancreas reduces the production of pancreatic enzymes that aid digestion, which can result in malnutrition. Fats and nutrients are not absorbed properly, leading to loose, greasy stool known as steatorrhea. * Weight loss even when eating habits and amounts are normal. * Diabetes type 1: Chronic pan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
