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Triosephosphate Isomerase
Triose-phosphate isomerase (TPI or TIM) is an enzyme () that catalyzes the reversible interconversion of the triose phosphate isomers dihydroxyacetone phosphate and D-glyceraldehyde 3-phosphate. TPI plays an important role in glycolysis and is essential for efficient energy production. TPI has been found in nearly every organism searched for the enzyme, including animals such as mammals and insects as well as in fungi, plants, and bacteria. However, some bacteria that do not perform glycolysis, like ureaplasmas, lack TPI. In humans, deficiencies in TPI are associated with a progressive, severe neurological disorder called triose phosphate isomerase deficiency. Triose phosphate isomerase deficiency is characterized by chronic hemolytic anemia. While there are various mutations that cause this disease, most include the replacement of glutamic acid at position 104 with an aspartic acid. Triose phosphate isomerase is a highly efficient enzyme, performing the reaction billions ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enzyme
An enzyme () is a protein that acts as a biological catalyst by accelerating chemical reactions. The molecules upon which enzymes may act are called substrate (chemistry), substrates, and the enzyme converts the substrates into different molecules known as product (chemistry), products. Almost all metabolism, metabolic processes in the cell (biology), 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, 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 include Ribozyme, catalytic RNA molecules, also called ribozymes. They are sometimes descr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mutation
In biology, a mutation is an alteration in the nucleic acid sequence of the genome of an organism, virus, or extrachromosomal DNA. Viral genomes contain either DNA or RNA. Mutations result from errors during DNA or viral replication, mitosis, or meiosis or other types of damage to DNA (such as pyrimidine dimers caused by exposure to ultraviolet radiation), which then may undergo error-prone repair (especially microhomology-mediated end joining), cause an error during other forms of repair, or cause an error during replication ( translesion synthesis). Mutations may also result from substitution, insertion or deletion of segments of DNA due to mobile genetic elements. Mutations may or may not produce detectable changes in the observable characteristics ( phenotype) of an organism. Mutations play a part in both normal and abnormal biological processes including: evolution, cancer, and the development of the immune system, including junctional diversity. Mutati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transition State Analog
Transition state analogs (transition state analogues), are chemical compounds with a chemical structure that resembles the transition state of a substrate molecule in an enzyme-catalyzed chemical reaction. Enzymes interact with a substrate by means of strain or distortions, moving the substrate towards the transition state. Transition state analogs can be used as inhibitors in enzyme-catalyzed reactions by blocking the active site of the enzyme. Theory suggests that enzyme inhibitors which resembled the transition state structure would bind more tightly to the enzyme than the actual substrate. Examples of drugs that are transition state analog inhibitors include flu medications such as the neuraminidase inhibitor oseltamivir and the HIV protease inhibitors saquinavir in the treatment of AIDS. Transition state analogue The transition state of a structure can best be described in regards to statistical mechanics where the energies of bonds breaking and forming have an equa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Active Site
In biology and biochemistry, the active site is the region of an enzyme where substrate molecules bind and undergo a chemical reaction. The active site consists of amino acid residues that form temporary bonds with the substrate, the ''binding site'', and residues that catalyse a reaction of that substrate, the ''catalytic site''. Although the active site occupies only ~10–20% of the volume of an enzyme, it is the most important part as it directly catalyzes the chemical reaction. It usually consists of three to four amino acids, while other amino acids within the protein are required to maintain the tertiary structure of the enzymes. Each active site is evolved to be optimised to bind a particular substrate and catalyse a particular reaction, resulting in high specificity. This specificity is determined by the arrangement of amino acids within the active site and the structure of the substrates. Sometimes enzymes also need to bind with some cofactors to fulfil their functio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arsenate
The arsenate is an ion with the chemical formula . Bonding in arsenate consists of a central arsenic atom, with oxidation state +5, double bonded to one oxygen atom and single bonded to a further three oxygen atoms. The four oxygen atoms orient around the arsenic atom in a tetrahedral geometry. Resonance disperses the ion's −3 charge across all four oxygen atoms. Arsenate readily reacts with metals to form arsenate metal compounds. Arsenate is a moderate oxidizer and an electron acceptor, with an electrode potential of +0.56 V for its reduction to arsenite. Due to arsenic having the same valency and similar atomic radius to phosphorus, arsenate shares similar geometry and reactivity with phosphate. Arsenate can replace phosphate in biochemical reactions and is toxic to most organisms. Natural occurrence Arsenates occur naturally, in hydrated and anhydrous form, in a variety of minerals. Examples of arsenate-containing minerals include adamite, alarsite, annaber ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phosphate
Phosphates are the naturally occurring form of the element phosphorus. In chemistry, a phosphate is an anion, salt, functional group or ester derived from a phosphoric acid. It most commonly means orthophosphate, a derivative of orthophosphoric acid, phosphoric acid . The phosphate or orthophosphate ion is derived from phosphoric acid by the removal of three protons . Removal of one proton gives the dihydrogen phosphate ion while removal of two protons gives the hydrogen phosphate ion . These names are also used for salts of those anions, such as ammonium dihydrogen phosphate and trisodium phosphate. File:3-phosphoric-acid-3D-balls.png, Phosphoricacid File:2-dihydrogenphosphate-3D-balls.png, Dihydrogenphosphate File:1-hydrogenphosphate-3D-balls.png, Hydrogenphosphate File:0-phosphate-3D-balls.png, Phosphate or orthophosphate In organic chemistry, phosphate or orthophosphate is an organophosphate, an ester of orthophosphoric acid of the form where one ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sulfate
The sulfate or sulphate ion is a polyatomic anion with the empirical formula . Salts, acid derivatives, and peroxides of sulfate are widely used in industry. Sulfates occur widely in everyday life. Sulfates are salts of sulfuric acid and many are prepared from that acid. Spelling "Sulfate" is the spelling recommended by IUPAC, but "sulphate" was traditionally used in British English. Structure The sulfate anion consists of a central sulfur atom surrounded by four equivalent oxygen atoms in a tetrahedral arrangement. The symmetry of the isolated anion is the same as that of methane. The sulfur atom is in the +6 oxidation state while the four oxygen atoms are each in the −2 state. The sulfate ion carries an overall charge of −2 and it is the conjugate base of the bisulfate (or hydrogensulfate) ion, , which is in turn the conjugate base of , sulfuric acid. Organic sulfate esters, such as dimethyl sulfate, are covalent compounds and esters of sulfuric acid. The tetrahedral ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electrophile
In chemistry, an electrophile is a chemical species that forms bonds with nucleophiles by accepting an electron pair. Because electrophiles accept electrons, they are Lewis acids. Most electrophiles are positively Electric charge, charged, have an atom that carries a partial positive charge, or have an atom that does not have an octet of electrons. Electrophiles mainly interact with nucleophiles through Addition reaction, addition and Substitution reaction, substitution reactions. Frequently seen electrophiles in Organic synthesis, organic syntheses include cations such as Hydrogen ion, H+ and nitrosonium, NO+, polarized neutral molecules such as hydrogen chloride, HCl, alkyl halides, acyl halides, and carbonyl compounds, polarizable neutral molecules such as chlorine, Cl2 and bromine, Br2, oxidizing agents such as organic peracids, chemical species that do not satisfy the octet rule such as carbenes and Radical (chemistry), radicals, and some Lewis acids such as Borane, BH3 and Di ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enzyme Substrate
In chemistry, the term substrate is highly context-dependent. Broadly speaking, it can refer either to a chemical species being observed in a chemical reaction, or to a surface on which other chemical reactions or microscopy are performed. In the former sense, a reagent is added to the ''substrate'' to generate a product through a chemical reaction. The term is used in a similar sense in synthetic and organic chemistry, where the substrate is the chemical of interest that is being modified. In biochemistry, an enzyme substrate is the material upon which an enzyme acts. When referring to Le Chatelier's principle, the substrate is the reagent whose concentration is changed. ;Spontaneous reaction : :*Where S is substrate and P is product. ;Catalysed reaction : :*Where S is substrate, P is product and C is catalyst. In the latter sense, it may refer to a surface on which other chemical reactions are performed or play a supporting role in a variety of spectroscopic and micro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nucleophile
In chemistry, a nucleophile is a chemical species that forms bonds by donating an electron pair. All molecules and ions with a free pair of electrons or at least one pi bond can act as nucleophiles. Because nucleophiles donate electrons, they are Lewis bases. ''Nucleophilic'' describes the affinity of a nucleophile to bond with positively charged Atomic nucleus, atomic nuclei. Nucleophilicity, sometimes referred to as nucleophile strength, refers to a substance's nucleophilic character and is often used to compare the affinity of atoms. Neutral nucleophilic reactions with solvents such as Alcohol (chemistry), alcohols and water are named solvolysis. Nucleophiles may take part in nucleophilic substitution, whereby a nucleophile becomes attracted to a full or partial positive charge, and nucleophilic addition. Nucleophilicity is closely related to basicity. The difference between the two is, that basicity is a thermodynamic property (i.e. relates to an equilibrium state), but nucleop ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
