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  • assay
  • In the homogeneous assay, an enzyme modulator (antibody, inhibitor or receptor for the enzyme) is covalently linked to the ligand which competes with free ligand from the test sample for the available antibodies. (wikipedia.org)
  • restriction enzyme
  • A restriction enzyme or restriction endonuclease is an enzyme that cleaves DNA into fragments at or near specific recognition sites within the molecule known as restriction sites. (wikipedia.org)
  • The term restriction enzyme originated from the studies of phage λ, a virus that infects bacteria, and the phenomenon of host-controlled restriction and modification of such bacterial phage or bacteriophage. (wikipedia.org)
  • In the 1960s, it was shown in work done in the laboratories of Werner Arber and Matthew Meselson that the restriction is caused by an enzymatic cleavage of the phage DNA, and the enzyme involved was therefore termed a restriction enzyme. (wikipedia.org)
  • In 1970, Hamilton O. Smith, Thomas Kelly and Kent Wilcox isolated and characterized the first type II restriction enzyme, HindII, from the bacterium Haemophilus influenzae. (wikipedia.org)
  • EcoRI digestion produces "sticky" ends, whereas SmaI restriction enzyme cleavage produces "blunt" ends: Recognition sequences in DNA differ for each restriction enzyme, producing differences in the length, sequence and strand orientation (5' end or 3' end) of a sticky-end "overhang" of an enzyme restriction. (wikipedia.org)
  • molecule
  • An artificial enzyme is a synthetic, organic molecule or ion that recreate some function of an enzyme. (wikipedia.org)
  • An enzyme mimic is a small molecule complex that models the molecular structure, spectroscopic properties, or reactivity of an enzyme, sometimes called bioinspired complexes. (wikipedia.org)
  • however, it has been increasingly common for groups to intentionally make small molecule analogs also known as enzyme mimics. (wikipedia.org)
  • The enzyme (EC 2.7.1.90) catalyses the reversible interconversion of fructose 6-phosphate and fructose 1,6-bisphosphate using inorganic pyrophosphate as the phosphoryl donor: diphosphate + D-fructose 6-phosphate ⇌ {\displaystyle \rightleftharpoons } phosphate + D-fructose 1,6-bisphosphate In plants, the PFP is located in the cytosol of the cell and is strongly activated by the signal molecule fructose 2,6-bisphosphate. (wikipedia.org)
  • monofunctional
  • Depending on the organism, the capping enzyme is either a monofunctional or bifunctional polypeptide. (wikipedia.org)
  • This means firstly that a specialist enzyme (monofunctional) when evolved goes through a generalist stage (multifunctional), before becoming a specialist again-presumably after gene duplication according to the IAD model-and secondly that promiscuous activities are more plastic than the main activity. (wikipedia.org)
  • methyltransferase
  • Three enzymes, RNA triphosphatase, guanylyltransferase (or CE), and methyltransferase are involved in the addition of the methylated 5' cap to the mRNA. (wikipedia.org)
  • Capping is a three-step process that utilizes the enzymes RNA triphosphatase, guanylyltransferase, and methyltransferase. (wikipedia.org)
  • meanwhile, host DNA is protected by a modification enzyme (a methyltransferase) that modifies the prokaryotic DNA and blocks cleavage. (wikipedia.org)
  • bifunctional
  • The human capping enzyme is an example of a bifunctional polypeptide, which has both triphosphatase (N-terminal) and guanylyltransferase (C-teriminal) domains. (wikipedia.org)
  • characterization
  • For their work in the discovery and characterization of restriction enzymes, the 1978 Nobel Prize for Physiology or Medicine was awarded to Werner Arber, Daniel Nathans, and Hamilton O. Smith. (wikipedia.org)
  • molecular
  • These enzymes are routinely used for DNA modification in laboratories, and they are a vital tool in molecular cloning. (wikipedia.org)
  • Two most common types of oxidative enzymes are peroxidases, which use hydrogen peroxide, and oxidases, which use molecular oxygen. (wikipedia.org)
  • katal
  • Since the minute is not an SI unit, the enzyme unit is discouraged in favour of the katal, the unit recommended by the General Conference on Weights and Measures in 1978 and officially adopted in 1999. (wikipedia.org)
  • available commercially
  • Over 200 nicking enzymes have been studied, and 13 of these are available commercially and are routinely used for research and in commercial products. (wikipedia.org)
  • Over 3000 restriction enzymes have been studied in detail, and more than 600 of these are available commercially. (wikipedia.org)
  • hydrogen
  • Reversible inhibitors attach to enzymes with non-covalent interactions such as hydrogen bonds, hydrophobic interactions and ionic bonds. (wikipedia.org)
  • covalent
  • The capping enzyme is part of the covalent nucleotidyl transferases superfamily, which also includes DNA ligases and RNA ligases. (wikipedia.org)
  • The enzymes of this superfamily share the following similarities: Conserved regions known as motifs I, II, III, IIIa, IV, V and VI, which are arranged in the same order and similar spacing A lysine containing motif KxDG (motif I) A covalent lysyl-NMP intermediate The capping enzyme is composed of two domains, a nucleotidyl transferase (NTase) domain and a C-terminal oligonucleotide binding (OB) domain. (wikipedia.org)
  • The NTase domain, conserved in capping enzymes, DNA and RNA ligases, is made up 5 motifs, I, III, IIIa, IV and V. Motif I or KxDG is the active site where the covalent (lysyl)-N-GMP intermediate is formed. (wikipedia.org)
  • Irreversible inhibitors usually react with the enzyme and change it chemically (e.g. via covalent bond formation). (wikipedia.org)
  • cellular
  • Some other examples of enzymes are phosphofructokinase and hexokinase, both of which are important for cellular respiration (glycolysis). (wikipedia.org)
  • Digestive enzymes are found in the digestive tracts of animals (including humans) and in the traps of carnivorous plants, where they aid in the digestion of food, as well as inside cells, especially in their lysosomes, where they function to maintain cellular survival. (wikipedia.org)
  • suggests
  • Knowing these properties suggests what an enzyme might do in the cell and can show how the enzyme will respond to changes in these conditions. (wikipedia.org)
  • Evidence gained from reconstructed enzyme suggests that the order of the events where the novel activity is improved and the gene is duplication is not clear cut, unlike what the theoretical models of gene evolution suggest. (wikipedia.org)
  • The induced fit only suggests that the barrier is lower in the closed form of the enzyme but does not tell us what the reason for the barrier reduction is. (wikipedia.org)
  • inhibitor
  • This is a measure of the amount of active enzyme, calculated by e.g. titrating the amount of active sites present by employing an irreversible inhibitor. (wikipedia.org)
  • laboratory
  • Restriction enzymes of this type are more useful for laboratory work as they cleave DNA at the site of their recognition sequence. (wikipedia.org)
  • example
  • although it is true that both measure chemical activity and that for many enzymes 1 U = 1 IU (because for many enzymes the existing U was adopted as the newer IU), international units can be defined for the biologic activity of many kinds of substance besides enzymes (for example, vitamins and hormones). (wikipedia.org)
  • For example, enzymes in a metabolic pathway can be inhibited by downstream products. (wikipedia.org)
  • The most recent and most clear cut example of enzyme evolution is the rise of bioremediating enzymes in the past 60 years. (wikipedia.org)
  • An example of an enzyme activator working in this way is fructose 2,6-bisphosphate, which activates phosphofructokinase 1 and increases the rate of glycolysis in response to the hormone insulin. (wikipedia.org)
  • activity
  • Although radiometric assays require the removal and counting of samples (i.e., they are discontinuous assays) they are usually extremely sensitive and can measure very low levels of enzyme activity. (wikipedia.org)
  • Since blocking an enzyme's activity can kill a pathogen or correct a metabolic imbalance, many drugs are enzyme inhibitors. (wikipedia.org)
  • On the other, enzymes may evolve an increased secondary activity with little loss to the primary activity ("robustness") with little adaptive conflict (§ Robustness and plasticity below). (wikipedia.org)
  • Enzyme activity is a measure of the quantity of active enzyme present and is thus dependent on conditions, which should be specified. (wikipedia.org)
  • The specific activity of an enzyme is another common unit. (wikipedia.org)
  • Specific activity gives a measurement of enzyme purity in the mixture. (wikipedia.org)
  • The specific activity should then be expressed as μmol min−1 mg−1 active enzyme. (wikipedia.org)
  • The % purity is 100% × (specific activity of enzyme sample / specific activity of pure enzyme). (wikipedia.org)
  • The impure sample has lower specific activity because some of the mass is not actually enzyme. (wikipedia.org)
  • If the specific activity of 100% pure enzyme is known, then an impure sample will have a lower specific activity, allowing purity to be calculated. (wikipedia.org)
  • known
  • A nicking enzyme (or nicking endonuclease) is an enzyme that cuts one strand of a double-stranded DNA at a specific recognition nucleotide sequences known as a restriction site. (wikipedia.org)
  • differences
  • For elimination of errors arising from differences in cultivation batches and/or misfolded enzyme etc. an active site titration needs to be done. (wikipedia.org)
  • gene
  • Restriction enzymes likely evolved from a common ancestor and became widespread via horizontal gene transfer. (wikipedia.org)
  • active site
  • The structure of some enzymes are very well characterized, however, the function of some component of the active site is poorly understood. (wikipedia.org)
  • proximity effects
  • However, the situation might be more complex, since modern computational studies have established that traditional examples of proximity effects cannot be related directly to enzyme entropic effects. (wikipedia.org)