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Deoxyribodipyrimidine Endonucleosidase
Deoxyribodipyrimidine endonucleosidase (, ''pyrimidine dimer DNA-glycosylase'', ''endonuclease V'', ''deoxyribonucleate pyrimidine dimer glycosidase'', ''pyrimidine dimer DNA glycosylase'', ''T4-induced UV endonuclease'', ''PD-DNA glycosylase'') is an enzyme with systematic name ''deoxy-D-ribocyclobutadipyrimidine polynucleotidodeoxyribohydrolase''. This enzyme catalyses the following chemical reaction : Cleaves the N-glycosidic bond between the 5'-pyrimidine residue in cyclobutadipyrimidine (in DNA) and the corresponding deoxy-D-ribose residue The only family of enzymes known to have this activity is represented by a phage T4 protein. This family also has AP lyase The enzyme DNA-(apurinic or apyrimidinic site) lyase, also referred to as DNA-(apurinic or apyrimidinic site) 5'-phosphomonoester-lyase (systematic name) or DNA AP lyase (EC 4.2.99.18) catalyzes the cleavage of the C-O-P bond 3' from the apurinic ... activity against the AP site produced by this reaction. Refe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enzyme
Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products. Almost all metabolic processes in the cell need enzyme catalysis in order to occur at rates fast enough to sustain life. Metabolic pathways depend upon enzymes to catalyze individual steps. The study of enzymes is called ''enzymology'' and the field of pseudoenzyme analysis recognizes that during evolution, some enzymes have lost the ability to carry out biological catalysis, which is often reflected in their amino acid sequences and unusual 'pseudocatalytic' properties. Enzymes are known to catalyze more than 5,000 biochemical reaction types. Other biocatalysts are catalytic RNA molecules, called ribozymes. Enzymes' specificity comes from their unique three-dimensional structures. Like all catalysts, enzymes increase the reaction ra ... [...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] |
Catalysis
Catalysis () is the process of increasing the rate of a chemical reaction by adding a substance known as a catalyst (). Catalysts are not consumed in 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 intermediates that subsequently give the final reaction product, in the process of regenerating the catalyst. Catalysis may be classified as either homogeneous, whose components are dispersed in the same phase (usually gaseous or liquid) as the reactant, or heterogeneous, whose components are not in the same phase. Enzymes and other biocatalysts are often considered as a third category. Catalysis is ubiquitous in chemical industry of all kinds. Estimates are that 90% of all commercially produced chemical products involve catalysts at some s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chemical Reaction
A chemical reaction is a process that leads to the IUPAC nomenclature for organic transformations, chemical transformation of one set of chemical substances to another. Classically, chemical reactions encompass changes that only involve the positions of electrons in the forming and breaking of chemical bonds between atoms, with no change to the Atomic nucleus, nuclei (no change to the elements present), and can often be described by a chemical equation. Nuclear chemistry is a sub-discipline of chemistry that involves the chemical reactions of unstable and radioactive Chemical element, elements where both electronic and nuclear changes can occur. The substance (or substances) initially involved in a chemical reaction are called reagent, reactants or reagents. Chemical reactions are usually characterized by a chemical change, and they yield one or more Product (chemistry), products, which usually have properties different from the reactants. Reactions often consist of a sequence o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
N-glycosidic Bond
A glycosidic bond or glycosidic linkage is a type of covalent bond that joins a carbohydrate (sugar) molecule to another group, which may or may not be another carbohydrate. A glycosidic bond is formed between the hemiacetal or hemiketal group of a saccharide (or a molecule derived from a saccharide) and the hydroxyl group of some compound such as an Alcohol (chemistry), alcohol. A substance containing a glycosidic bond is a glycoside. The term 'glycoside' is now extended to also cover compounds with bonds formed between hemiacetal (or hemiketal) groups of sugars and several chemical groups other than hydroxyls, such as -SR (thioglycosides), -SeR (selenoglycosides), -NR1R2 (N-glycosides), or even -CR1R2R3 (C-glycosides). Particularly in naturally occurring glycosides, the compound ROH from which the carbohydrate residue has been removed is often termed the aglycone, and the carbohydrate residue itself is sometimes referred to as the 'glycone'. S-, N-, C-, and O-glycosidic ... [...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] |
Deoxyribose
Deoxyribose, or more precisely 2-deoxyribose, is a monosaccharide with idealized formula H−(C=O)−(CH2)−(CHOH)3−H. Its name indicates that it is a deoxy sugar, meaning that it is derived from the sugar ribose by loss of a hydroxy group. Discovered in 1929 by Phoebus Levene, deoxyribose is most notable for its presence in DNA. Since the pentose sugars arabinose and ribose only differ by the stereochemistry at C2′, 2-deoxyribose and 2-deoxyarabinose are equivalent, although the latter term is rarely used because ribose, not arabinose, is the precursor to deoxyribose. Structure Several isomers exist with the formula H−(C=O)−(CH2)−(CHOH)3−H, but in deoxyribose all the hydroxyl groups are on the same side in the Fischer projection. The term "2-deoxyribose" may refer to either of two enantiomers: the biologically important -2-deoxyribose and to the rarely encountered mirror image -2-deoxyribose.C Bernelot-Moens and B Demple (1989), ''Multiple DNA repair activities f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phage T4
Escherichia virus T4 is a species of bacteriophages that infect ''Escherichia coli'' bacteria. It is a double-stranded DNA virus in the subfamily ''Tevenvirinae'' from the family Myoviridae. T4 is capable of undergoing only a lytic lifecycle and not the lysogenic lifecycle. The species was formerly named T-even bacteriophage, a name which also encompasses, among other strains (or isolates), Enterobacteria phage T2, Enterobacteria phage T4 and Enterobacteria phage T6. Use in research Dating back to the 1940s and continuing today, T-even phages are considered the best studied model organisms. Model organisms are usually required to be simple with as few as five genes. Yet, T-even phages are in fact among the largest and highest complexity virus, in which these phage's genetic information is made up of around 300 genes. Coincident with their complexity, T-even viruses were found to have the unusual base hydroxymethylcytosine (HMC) in place of the nucleic acid base cytosine. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DNA-(apurinic Or Apyrimidinic Site) Lyase
The enzyme DNA-(apurinic or apyrimidinic site) lyase, also referred to as DNA-(apurinic or apyrimidinic site) 5'-phosphomonoester-lyase (systematic name) or DNA AP lyase (EC 4.2.99.18) catalyzes the cleavage of the C-O-P bond 3' from the apurinic or apyrimidinic site in DNA via β-elimination reaction, leaving a 3'-terminal unsaturated sugar and a product with a terminal 5'-phosphate. In the 1970s, this class of enzyme was found to repair at apurinic or apyrimidinic DNA sites in ''E. coli'' and in mammalian cells. The major active enzyme of this class in bacteria, and specifically, ''E. coli'' is endonuclease type III. This enzyme is part of a family of lyases that cleave carbon-oxygen bonds. Other names for DNA AP lyase include: AP lyase; AP endonuclease class I; endodeoxyribonuclease (apurinic or apyrimidinic); deoxyribonuclease (apurinic or apyrimidinic); E. coli endonuclease III; phage-T4 UV endonuclease; Micrococcus luteus UV endonuclease; AP site-DNA 5'-phosphomonoester-l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
AP Site
In biochemistry and molecular genetics, an AP site (apurinic/apyrimidinic site), also known as an abasic site, is a location in DNA (also in RNA but much less likely) that has neither a purine nor a pyrimidine base, either spontaneously or due to DNA damage. It has been estimated that under physiological conditions 10,000 apurinic sites and 500 apyrimidinic may be generated in a cell daily. AP sites can be formed by spontaneous depurination, but also occur as intermediates in base excision repair.Abasic sites in DNA: repair and biological consequences in Saccharomyces cerevisiae. DNA Repair (Amst). 2004 Jan 5;3(1):1-12. In this process, a DNA glycosylase recognizes a damaged base and cleaves the N-glycosidic bond to release the base, leaving an AP site. A variety of glycosylases that recognize different types of damage exist, including oxidized or methylated bases, or uracil in DNA. The AP site can then be cleaved by an AP endonuclease, leaving 3'-hydroxyl and deoxyribose-5-ph ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
