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| [[Image:Lineweaver-Burke plot.svg|350px|right]]
| | Im addicted to my hobby Martial arts. <br>I to learn Spanish in my free time.<br><br>Also visit my webpage ... [http://ebook-pdfree.blogspot.com/2014/08/free-download-abundance-of-katherines.html An Abundance of Katherines pdf] |
| 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.<ref>{{cite journal | author = Lineweaver, H and Burk, D. | year = 1934 | title = The Determination of Enzyme Dissociation Constants | journal = Journal of the American Chemical Society | volume = 56 | pages = 658–666 | doi = 10.1021/ja01318a036 | issue = 3}}</ref>
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| ==Derivation==
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| The plot provides a useful graphical method for analysis of the [[Michaelis–Menten kinetics|Michaelis–Menten]] equation:
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| :<math>V = \frac{V_{\max} [S]}{K_m + [S]} </math>
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| Taking the reciprocal gives
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| :<math>{1 \over V} = {{K_m + [S]} \over V_{\max}[S]} = {K_m \over V_\max} {1 \over [S]} + {1 \over V_\max}</math>
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| where ''V'' is the reaction velocity (the [[reaction rate]]), ''K''<sub>''m''</sub> is the [[Michaelis–Menten constant]], ''V''<sub>max</sub> is the maximum reaction velocity, and [''S''] is the substrate [[concentration]].
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| ==Use==
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| [[File:Inhibition diagrams.png|thumb|200px|right|Lineweaver–Burk plots of different types of reversible enzyme inhibitors. The arrow shows the effect of increasing concentrations of inhibitor.]]
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| The Lineweaver–Burk plot was widely used to determine important terms in enzyme kinetics, such as ''K''<sub>''m''</sub> and ''V''<sub>max</sub>, before the wide availability of powerful computers and [[Nonlinear regression|non-linear regression]] software. The [[y-intercept|''y''-intercept]] of such a graph is equivalent to the inverse of ''V''<sub>max</sub>; the [[root of a function|''x''-intercept]] of the graph represents −1/''K''<sub>''m''</sub>. It also gives a quick, visual impression of the different forms of [[enzyme inhibition]].
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| The double reciprocal plot distorts the error structure of the data, and it is therefore unreliable for the determination of enzyme kinetic parameters. Although it is still used for representation of kinetic data,<ref name="hayakawa06">
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| {{cite journal
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| | last1 = Hayakawa
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| | first1 = K.
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| | last2 = Guo
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| | first2 = L.
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| | last3 = Terentyeva
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| | first3 = E.A.
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| | last4 = Li
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| | first4 = X.K.
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| | last5 = Kimura
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| | first5 = H.
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| | last6 = Hirano
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| | first6 = M.
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| | last7 = Yoshikawa
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| | first7 = K.
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| | last8 = Nagamine
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| | first8 = T.
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| | last9 = Katsumata
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| | first9 = N.
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| | last10 = Ogata
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| | first10 = Tsutomu
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| | last11 = Tanaka
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| | first11 = Toshiaki
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| | title = Determination of specific activities and kinetic constants of biotinidase and lipoamidase in LEW rat and Lactobacillus casei (Shirota)
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| | journal = J Chromatogr B Analyt Technol Biomed Life Sci
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| | volume = 844
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| | issue = 2
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| | pages = 240–50
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| | year = 2006
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| | doi = 10.1016/j.jchromb.2006.07.006
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| | pmid = 16876490
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| | display-authors = 8
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| }}
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| </ref> non-linear regression or alternative linear forms of the [[Michaelis–Menten kinetics|Michaelis–Menten]] equation such as the [[Hanes-Woolf plot]] or [[Eadie–Hofstee plot]] are generally used for the calculation of parameters.<ref>{{cite journal
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| | author = Greco, W. R. and Hakala, M. T.,
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| | title = Evaluation of methods for estimating the dissociation constant of tight binding enzyme inhibitors,
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| | journal = J. Biol. Chem.
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| | volume = 254
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| | issue = 23
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| | pages = 12104–12109
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| | year = 1979
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| | url = http://www.jbc.org/cgi/reprint/254/23/12104.pdf
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| | pmid = 500698|format=PDF }}</ref>
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| When used for determining the type of enzyme inhibition, the Lineweaver–Burk plot can distinguish [[Competitive inhibition|competitive]], [[Non-competitive inhibition|non-competitive]] and [[Uncompetitive inhibition|uncompetitive]] inhibitors. Competitive inhibitors have the same ''y''-intercept as uninhibited enzyme (since ''V''<sub>max</sub> is unaffected by competitive inhibitors the inverse of ''V''<sub>max</sub> also doesn't change) but there are different slopes and ''x''-intercepts between the two data sets. Non-competitive inhibition produces plots with the same ''x''-intercept as uninhibited enzyme (''K''<sub>''m''</sub> is unaffected) but different slopes and ''y''-intercepts. Uncompetitive inhibition causes different intercepts on both the ''y''- and ''x''-axes but the same slope.
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| ==Problems with the method==
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| The Lineweaver–Burk plot is classically used in older texts, but is prone to error, as the ''y''-axis takes the reciprocal of the rate of reaction – in turn increasing any small errors in measurement. Also, most points on the plot are found far to the right of the ''y''-axis (due to limiting solubility not allowing for large values of [S] and hence no small values for 1/[S]), calling for a large extrapolation back to obtain ''x''- and ''y''-intercepts.<ref>Dowd, John E., and Douglas S. Riggs. "A comparison of estimates of Michaelis-Menten kinetic constants from various linear transformations." J. biol. Chem 240.2 (1965): 863-869.</ref>
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| ==See also==
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| * [[Michaelis–Menten kinetics]]
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| * [[Eadie–Hofstee diagram]]
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| * [[Hanes–Woolf plot]]
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| ==References==
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| {{reflist|1}}
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| == External links ==
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| * [http://www.ncgc.nih.gov/guidance/section4.html#inhibition-constant NIH guide], enzyme assay development and analysis
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| {{Enzymes}}
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| {{DEFAULTSORT:Lineweaver-Burk plot}}
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| [[Category:Plots (graphics)]]
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| [[Category:Enzyme kinetics]]
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Im addicted to my hobby Martial arts.
I to learn Spanish in my free time.
Also visit my webpage ... An Abundance of Katherines pdf