|
DPYD
In enzymology, a dihydropyrimidine dehydrogenase (NADP+) () is an enzyme that catalyzes the chemical reaction :5,6-dihydrouracil + NADP+ \rightleftharpoons uracil + NADPH + H+ Thus, the two substrates of this enzyme are 5,6-dihydrouracil and NADP+, whereas its 3 products are uracil, NADPH, and H+. In humans the enzyme is encoded by the ''DPYD'' gene. It is the initial and rate-limiting step in pyrimidine catabolism. It catalyzes the reduction of uracil and thymine. It is also involved in the degradation of the chemotherapeutic drugs 5-fluorouracil and tegafur. It also participates in beta-alanine metabolism and pantothenate and coa biosynthesis. Terminology The systematic name of this enzyme class is 5,6-dihydrouracil:NADP+ 5-oxidoreductase. Other names in common use include: * dihydrothymine dehydrogenase *dihydrouracil dehydrogenase (NADP+) *4,5-dihydrothymine: oxidoreductase *DPD *DHPDH *dehydrogenase, dihydrouracil (nicotinamide adenine dinucleotide, phosphate) *DHU ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dihydropyrimidine Dehydrogenase Deficiency
Dihydropyrimidine dehydrogenase deficiency is an autosomal recessive metabolic disorder in which there is absent or significantly decreased activity of dihydropyrimidine dehydrogenase, an enzyme involved in the metabolism of uracil and thymine. Individuals with this condition may develop life-threatening toxicity following exposure to 5-fluorouracil (5-FU), a chemotherapy drug that is used in the treatment of cancer. Beside 5-FU, widely prescribed oral fluoropyrimidine capecitabine (Xeloda) could put DPD-deficient patients at risk of experiencing severe or lethal toxicities as well. Genetics DPD deficiency is inherited in an autosomal recessive manner. This means the defective gene responsible for the disorder is located on an autosome An autosome is any chromosome that is not a sex chromosome. The members of an autosome pair in a diploid cell have the same morphology, unlike those in allosome, allosomal (sex chromosome) pairs, which may have different structures. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cancer Pharmacogenomics
Cancer pharmacogenomics is the study of how variances in the genome influences an individual’s response to different cancer drug treatments. It is a subset of the broader field of pharmacogenomics, which is the area of study aimed at understanding how genetic variants influence drug efficacy and toxicity. Cancer is a genetic disease where changes to genes can cause cells to grow and divide out of control. Each cancer can have a unique combination of genetic mutations, and even cells within the same tumour may have different genetic changes. In clinical settings, it has commonly been observed that the same types and doses of treatment can result in substantial differences in efficacy and toxicity across patients. Thus, the application of pharmacogenomics within the field of cancer can offer key advantages for personalizing cancer therapy, minimizing treatment toxicity, and maximizing treatment efficacy. This can include choosing drugs that target specific mutations within cancer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
5-fluorouracil
Fluorouracil (5-FU), sold under the brand name Adrucil among others, is a cytotoxic chemotherapy medication used to treat cancer. By intravenous injection it is used for treatment of colorectal cancer, oesophageal cancer, stomach cancer, pancreatic cancer, breast cancer, and cervical cancer. As a cream it is used for actinic keratosis, basal cell carcinoma, and skin warts. Side effects of use by injection are common. They may include inflammation of the mouth, loss of appetite, low blood cell counts, hair loss, and inflammation of the skin. When used as a cream, irritation at the site of application usually occurs. Use of either form in pregnancy may harm the baby. Fluorouracil is in the antimetabolite and pyrimidine analog families of medications. How it works is not entirely clear, but it is believed to involve blocking the action of thymidylate synthase and thus stopping the production of DNA. Fluorouracil was patented in 1956 and came into medical use in 1962. It is on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tegafur
Tegafur is a chemotherapeutic prodrug of 5-fluorouracil (5-FU) used in the treatment of cancers. It is a component of the combination drug tegafur/uracil. When metabolised, it becomes 5-FU. It was patented in 1967 and approved for medical use in 1972. Medical uses As a prodrug to 5-FU it is used in the treatment of the following cancers: * Stomach cancer, Stomach (when combined with Tegafur/gimeracil/oteracil, gimeracil and oteracil) * Breast cancer, Breast (with uracil) * Gallbladder cancer, Gallbladder * Lung cancer, Lung (specifically adenocarcinoma, typically with uracil) * Colorectal cancer, Colorectal (usually when combined with gimeracil and oteracil) * Head and neck cancer, Head and neck * Liver cancer, Liver (with uracil) * Pancreatic cancer, Pancreatic It is often given in combination with drugs that alter its bioavailability and toxicity such as gimeracil, oteracil or uracil. These agents achieve this by inhibiting the enzyme dihydropyrimidine dehydrogenase (uracil/gi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Catabolism
Catabolism () is the set of metabolic pathways that breaks down molecules into smaller units that are either oxidized to release energy or used in other anabolic reactions. Catabolism breaks down large molecules (such as polysaccharides, lipids, nucleic acids, and proteins) into smaller units (such as monosaccharides, fatty acids, nucleotides, and amino acids, respectively). Catabolism is the breaking-down aspect of metabolism, whereas anabolism is the building-up aspect. Cells use the monomers released from breaking down polymers to either construct new polymer molecules or degrade the monomers further to simple waste products, releasing energy. Cellular wastes include lactic acid, acetic acid, carbon dioxide, ammonia, and urea. The formation of these wastes is usually an oxidation process involving a release of chemical free energy, some of which is lost as heat, but the rest of which is used to drive the synthesis of adenosine triphosphate (ATP). This molecule acts as a way f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thymidine
Thymidine (symbol dT or dThd), also known as deoxythymidine, deoxyribosylthymine, or thymine deoxyriboside, is a pyrimidine deoxynucleoside. Deoxythymidine is the DNA nucleoside T, which pairs with deoxyadenosine (A) in double-stranded DNA. In cell biology it is used to synchronize the cells in G1/early S phase. The prefix deoxy- is often left out since there are no precursors of thymine nucleotides involved in RNA synthesis. Before the boom in thymidine use caused by the need for thymidine in the production of the antiretroviral drug azidothymidine (AZT), much of the world's thymidine production came from herring sperm. Thymidine occurs almost exclusively in DNA but it also occurs in the T-loop of tRNA. Structure and properties In its composition, deoxythymidine is a nucleoside composed of deoxyribose (a pentose sugar) joined to the pyrimidine base thymine. Deoxythymidine can be phosphorylated with one, two or three phosphoric acid groups, creating dTMP (deoxythymidine ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pyrimidine
Pyrimidine (; ) is an aromatic, heterocyclic, organic compound similar to pyridine (). One of the three diazines (six-membered heterocyclics with two nitrogen atoms in the ring), it has nitrogen atoms at positions 1 and 3 in the ring. The other diazines are pyrazine (nitrogen atoms at the 1 and 4 positions) and pyridazine (nitrogen atoms at the 1 and 2 positions). In nucleic acids, three types of nucleobases are pyrimidine derivatives: cytosine (C), thymine (T), and uracil (U). Occurrence and history The pyrimidine ring system has wide occurrence in nature as substituted and ring fused compounds and derivatives, including the nucleotides cytosine, thymine and uracil, thiamine (vitamin B1) and alloxan. It is also found in many synthetic compounds such as barbiturates and the HIV drug, zidovudine. Although pyrimidine derivatives such as alloxan were known in the early 19th century, a laboratory synthesis of a pyrimidine was not carried out until 1879, when Grimaux reported the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protein Data Bank
The Protein Data Bank (PDB) is a database for the three-dimensional structural data of large biological molecules, such as proteins and nucleic acids. The data, typically obtained by X-ray crystallography, NMR spectroscopy, or, increasingly, cryo-electron microscopy, and submitted by biologists and biochemists from around the world, are freely accessible on the Internet via the websites of its member organisations (PDBe, PDBj, RCSB, and BMRB). The PDB is overseen by an organization called the Worldwide Protein Data Bank, wwPDB. The PDB is a key in areas of structural biology, such as structural genomics. Most major scientific journals and some funding agencies now require scientists to submit their structure data to the PDB. Many other databases use protein structures deposited in the PDB. For example, SCOP and CATH classify protein structures, while PDBsum provides a graphic overview of PDB entries using information from other sources, such as Gene ontology. History Two force ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tertiary Structure
Protein tertiary structure is the three dimensional shape of a protein. The tertiary structure will have a single polypeptide chain "backbone" with one or more protein secondary structures, the protein domains. Amino acid side chains may interact and bond in a number of ways. The interactions and bonds of side chains within a particular protein determine its tertiary structure. The protein tertiary structure is defined by its atomic coordinates. These coordinates may refer either to a protein domain or to the entire tertiary structure.Branden C. and Tooze J. "Introduction to Protein Structure" Garland Publishing, New York. 1990 and 1991. A number of tertiary structures may fold into a quaternary structure.Kyte, J. "Structure in Protein Chemistry." Garland Publishing, New York. 1995. History The science of the tertiary structure of proteins has progressed from one of hypothesis to one of detailed definition. Although Emil Fischer had suggested proteins were made of polypept ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Enzymes
This article lists enzymes by their classification in the International Union of Biochemistry and Molecular Biology's Enzyme Commission (EC) numbering system. * List of EC numbers (EC 5) * List of EC numbers (EC 6) :Oxidoreductases (EC 1) (Oxidoreductase) *Dehydrogenase * Luciferase *DMSO reductase :EC 1.1 (act on the CH-OH group of donors) * :EC 1.1.1 (with NAD+ or NADP+ as acceptor) ** Alcohol dehydrogenase (NAD) ** Alcohol dehydrogenase (NADP) **Homoserine dehydrogenase ** Aminopropanol oxidoreductase **Diacetyl reductase **Glycerol dehydrogenase **Propanediol-phosphate dehydrogenase ** glycerol-3-phosphate dehydrogenase (NAD+) ** D-xylulose reductase **L-xylulose reductase **Lactate dehydrogenase **Malate dehydrogenase **Isocitrate dehydrogenase ** HMG-CoA reductase * :EC 1.1.2 (with a cytochrome as acceptor) * :EC 1.1.3 (with oxygen as acceptor) **Glucose oxidase **L-gulonolactone oxidase **Thiamine oxidase **Xanthine oxidase * :EC 1.1.4 (with a disul ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
