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Hanes–Woolf Plot
In biochemistry, a Hanes–Woolf plot, Hanes plot, or plot of a/v against a, is a graphical representation of enzyme kinetics in which the ratio of the initial substrate concentration a to the reaction velocity v is plotted against a. It is based on the rearrangement of the Michaelis–Menten equation shown below: : = + where K_\mathrm is the Michaelis constant and V is the limiting rate. J B S Haldane stated, reiterating what he and K. G. Stern had written in their book, that this rearrangement was due to Barnet Woolf. However, it was just one of three transformations introduced by Woolf, who did not use it as the basis of a plot. There is therefore no strong reason for attaching his name to it. It was first published by C. S. Hanes, though he did not use it as plot either. Hanes said that the use of linear regression to determine kinetic parameters from this type of linear transformation is flawed, because it generates the best fit between observed and calculated ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biochemistry
Biochemistry or biological chemistry is the study of chemical processes within and relating to living organisms. A sub-discipline of both chemistry and biology, biochemistry may be divided into three fields: structural biology, enzymology and metabolism. Over the last decades of the 20th century, biochemistry has become successful at explaining living processes through these three disciplines. Almost all areas of the life sciences are being uncovered and developed through biochemical methodology and research.Voet (2005), p. 3. Biochemistry focuses on understanding the chemical basis which allows biological molecules to give rise to the processes that occur within living cells and between cells, Karp (2009), p. 2. in turn relating greatly to the understanding of tissues and organs, as well as organism structure and function. Miller (2012). p. 62. Biochemistry is closely related to molecular biology, which is the study of the molecular mechanisms of biological phenom ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enzyme Kinetics
Enzyme kinetics is the study of the rates of enzyme-catalysed chemical reactions. In enzyme kinetics, the reaction rate is measured and the effects of varying the conditions of the reaction are investigated. Studying an enzyme's kinetics in this way can reveal the catalytic mechanism of this enzyme, its role in metabolism, how its activity is controlled, and how a drug or a modifier (inhibitor or activator) might affect the rate. An enzyme (E) is typically a protein molecule that promotes a reaction of another molecule, its substrate (S). This binds to the active site of the enzyme to produce an enzyme-substrate complex ES, and is transformed into an enzyme-product complex EP and from there to product P, via a transition state ES*. The series of steps is known as the mechanism: : E + S ⇄ ES ⇄ ES* ⇄ EP ⇄ E + P This example assumes the simplest case of a reaction with one substrate and one product. Such cases exist: for example, a mutase such as phosphoglucomutase ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reaction Velocity
The reaction rate or rate of reaction is the speed at which a chemical reaction takes place, defined as proportional to the increase in the concentration of a product per unit time and to the decrease in the concentration of a reactant per unit time. Reaction rates can vary dramatically. For example, the oxidative rusting of iron under Earth's atmosphere is a slow reaction that can take many years, but the combustion of cellulose in a fire is a reaction that takes place in fractions of a second. For most reactions, the rate decreases as the reaction proceeds. A reaction's rate can be determined by measuring the changes in concentration over time. Chemical kinetics is the part of physical chemistry that concerns how rates of chemical reactions are measured and predicted, and how reaction-rate data can be used to deduce probable reaction mechanisms. The concepts of chemical kinetics are applied in many disciplines, such as chemical engineering, enzymology and environmental engin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Michaelis Constant
Michaelis or Michelis is a surname. Notable people and characters with the surname include: * Adolf Michaelis, German classical scholar * Anthony R. Michaelis, German science writer * Edward Michelis, German theologian * Georg Michaelis, German politician * Gustav Adolf Michaelis, German obstetrician and namesake of the rhombus of Michaelis * Hans-Thorald Michaelis, German historian * Johann David Michaelis, German biblical scholar * John H. Michaelis, American four-star general * Laura Michaelis, American linguist * Leo Michelis, Greek-Canadian economist * Leonor Michaelis, German scientist known for Michaelis–Menten kinetics * Max Michaelis, South African financier * Margaret Michaelis-Sachs, Austrian-Australian photographer * Paul Charles Michaelis, American scientist * Peter Michaelis, German botanist * Robert Michaelis (1878–1965), French-born actor and singer who settled in England * Sebastian Michaelis, the demon butler from Kuroshitsuji * Sebastien Michaelis, Fre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
J B S Haldane
John Burdon Sanderson Haldane (; 5 November 18921 December 1964), nicknamed "Jack" or "JBS", was a British-Indian scientist who worked in physiology, genetics, evolutionary biology, and mathematics. With innovative use of statistics in biology, he was one of the founders of neo-Darwinism. He served in the Great War, and obtained the rank of captain. Despite his lack of an academic degree in the field, he taught biology at the University of Cambridge, the Royal Institution, and University College London. Renouncing his British citizenship, he became an Indian citizen in 1961 and worked at the Indian Statistical Institute for the rest of his life. Haldane's article on abiogenesis in 1929 introduced the "primordial soup theory", which became the foundation for the concept of the chemical origin of life. He established human gene maps for haemophilia and colour blindness on the X chromosome, and codified Haldane's rule on sterility in the heterogametic sex of hybrids in speci ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Barnet Woolf
Barnet Woolf FRSE (24 November 1902 – 20 March 1983) was a 20th-century British scientist, whose disciplines had a broad scope. He made lasting contributions to biochemistry, genetics, epidemiology, nutrition, public health, statistics, and computer science. His name appears in the Hanes-Woolf plot: a mathematical plotting of chemical reaction times. Life & Politics Born and raised in Hackney, the son of a cabinet maker, and influenced by the deprivation of the East End of London he joined the Communist Party as a founder member in 1920. In 1936 he helped to organise at Cable Street where demonstrators prevented the Mosleyites marching through the Jewish East End. He left the Party in 1939 due to the Molotov-Ribbentrop Pact but rejoined in 1941 when the USSR joined the war. He finally left in 1949 due to profound disagreement with the way Lysenko's flawed science was adopted in the Soviet Union. Science In 1921 Woolf gained a place at Sidney Sussex College, Cambridge,som ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nature (journal)
''Nature'' is a British weekly scientific journal founded and based in London, England. As a multidisciplinary publication, ''Nature'' features peer-reviewed research from a variety of academic disciplines, mainly in science and technology. It has core editorial offices across the United States, continental Europe, and Asia under the international scientific publishing company Springer Nature. ''Nature'' was one of the world's most cited scientific journals by the Science Edition of the 2019 '' Journal Citation Reports'' (with an ascribed impact factor of 42.778), making it one of the world's most-read and most prestigious academic journals. , it claimed an online readership of about three million unique readers per month. Founded in autumn 1869, ''Nature'' was first circulated by Norman Lockyer and Alexander Macmillan as a public forum for scientific innovations. The mid-20th century facilitated an editorial expansion for the journal; ''Nature'' redoubled its efforts in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lineweaver–Burk Plot
In biochemistry, the Lineweaver–Burk plot (or double reciprocal plot) is a graphical representation of the Lineweaver–Burk equation of enzyme kinetics, described by Hans Lineweaver and Dean Burk in 1934. The Lineweaver–Burk plot for inhibited enzymes can be compared to no inhibitor to determine how the inhibitor is competing with the enzyme. The Lineweaver–Burk plot is correct when the enzyme kinetics obey ideal second-order kinetics, however non-linear regression is needed for systems that do not behave ideally. The double reciprocal plot distorts the error structure of the data, and is therefore not the most accurate tool for the determination of enzyme kinetic parameters. While the Lineweaver–Burk plot has historically been used for evaluation of the parameters, together with the alternative linear forms of the Michaelis–Menten equation such as the Hanes-Woolf plot or Eadie–Hofstee plot, all linearized forms of the Michaelis–Menten equation should be avoided ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nonlinear Regression
In statistics, nonlinear regression is a form of regression analysis in which observational data are modeled by a function which is a nonlinear combination of the model parameters and depends on one or more independent variables. The data are fitted by a method of successive approximations. General In nonlinear regression, a statistical model of the form, : \mathbf \sim f(\mathbf, \boldsymbol\beta) relates a vector of independent variables, \mathbf, and its associated observed dependent variables, \mathbf. The function f is nonlinear in the components of the vector of parameters \beta, but otherwise arbitrary. For example, the Michaelis–Menten model for enzyme kinetics has two parameters and one independent variable, related by f by: : f(x,\boldsymbol\beta)= \frac This function is nonlinear because it cannot be expressed as a linear combination of the two ''\beta''s. Systematic error may be present in the independent variables but its treatment is outside the scop ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Michaelis–Menten Kinetics
In biochemistry, Michaelis–Menten kinetics is one of the best-known models of enzyme kinetics. It is named after German biochemist Leonor Michaelis and Canadian physician Maud Menten. The model takes the form of an equation describing the rate of enzymatic reactions, by relating reaction rate v (rate of formation of product, ce P/math>) to ce S/math>, the concentration of a substrate ''S''. Its formula is given by : v = \frac = V_\max \frac This equation is called the Michaelis–Menten equation. Here, V_\max represents the maximum rate achieved by the system, happening at saturating substrate concentration for a given enzyme concentration. When the value of the Michaelis constant K_\mathrm is numerically equal to the substrate concentration, then the reaction rate is half of V_\max. Biochemical reactions involving a single substrate are often assumed to follow Michaelis–Menten kinetics, without regard to the model's underlying assumptions. Model In 1901, Fre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
