WordNet

used of flowers having more than the usual number of petals in crowded or overlapping arrangements; "double chrysanthemums have many rows of petals and are usually spherical or hemispherical"
increase twofold; "The population doubled within 50 years" (同)duplicate
a base hit on which the batter stops safely at second base; "he hit a double to deep centerfield" (同)two-base hit, two-bagger, two-baser
someone who closely resembles a famous person (especially an actor); "he could be Gingrichs double"; "shes the very image of her mother" (同)image, look-alike
a stand-in for movie stars to perform dangerous stunts; "his first job in Hollywood was as a double for Clark Gable" (同)stunt man, stunt woman
a quantity that is twice as great as another; "36 is the double of 18"
twice as great or many; "ate a double portion"; "the dose is doubled"; "a twofold increase" (同)doubled, twofold, two-fold
consisting of or involving two parts or components usually in pairs; "an egg with a double yolk"; "a double (binary) star"; "double doors"; "dual controls for pilot and copilot"; "duple (or double) time consists of two (or a multiple of two) beats to a measure" (同)dual, duple
having more than one decidedly dissimilar aspects or qualities; "a double (or dual) role for an actor"; "the office of a clergyman is twofold; public preaching and private influence"- R.W.Emerson; "every episode has its double and treble meaning"-Frederick Harrison (同)dual, twofold, two-fold, treble, threefold, three-fold
having two meanings with intent to deceive; "a sly double meaning"; "spoke with forked tongue" (同)forked
bridge: make a demand for (a card or suit)
do double duty; serve two purposes or have two functions; "She doubles as his wife and secretary"
downward and forward; "he was bent double with pain"
hit a two-base hit
large enough for two; "a double bed"; "a double room"
two together; "some people sleep better double"
of or relating to the multiplicative inverse of a quantity or function; "the reciprocal ratio of a:b is b:a"
something (a term or expression or concept) that has a reciprocal relation to something else; "risk is the reciprocal of safety"
concerning each of two or more persons or things; especially given or done in return; "reciprocal aid"; "reciprocal trade"; "mutual respect"; "reciprocal privileges at other clubs" (同)mutual
increase by a factor of two; "doubling with a computer took no time at all"
raising the stakes in a card game by a factor of 2; "I decided his double was a bluff" (同)double
badminton played with two players on each side
tennis played with two players on each side

PrepTutorEJDIC

(数量・強さ・重さ・価値などが)『2倍の』,倍の / 『二重の』,二様の;複の,対の,2人用の / 表裏のある,二心ある / (意味が)二様にとれる,あいまいな / (花が)八重の,重弁の / 『2倍に』,2倍だけ(twice) / 二重に,二様に / 対をなして,二人いっしょに / 〈U〉『2倍』[の数量・価額など] / 〈C〉2倍のもの / 〈C〉よく似た人(物),生き写し / 〈C〉(映画の)代役 / 《複数形》《単数扱い》(テニスなどの)ダブルス / 〈C〉(獲物が追っ手を逃れるときなどの)逆走,急転回 / 〈C〉2塁打 / 〈C〉(ブリッジの点の)倍加 / 〈C〉(競馬・ドッグレースの)重勝式のかけ,複式 / …‘を'『2倍にする』 / …‘を'『二つ折りにする』 / …‘の'2倍の数(量)がある / 〈二役〉‘を'ひとりで演ずる / 〈船が〉〈岬〉‘を'回る / 『2倍になる』 / (…の役を)兼ねる《+『as』+『名』》 / (急に)取って返す,逆戻りする《+『back』》 / 二つ折りになる / (ブリッジで)相手のせり高を倍加する / 2塁打を打つ
相互の(mutual) / お返しの,報いの / (文法で)相互の / 逆数,反数

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2015/05/30 03:05:24」(JST)

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An example of a Lineweaver-Burke 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.^[1]

Derivation

The plot provides a useful graphical method for analysis of the Michaelis–Menten equation:

Taking the reciprocal gives

where V is the reaction velocity (the reaction rate), K_m is the Michaelis–Menten constant, V_max is the maximum reaction velocity, and [S] is the substrate concentration.

Use

Lineweaver–Burk plots of different types of reversible enzyme inhibitors. The arrow shows the effect of increasing concentrations of inhibitor.

The Lineweaver–Burk plot was widely used to determine important terms in enzyme kinetics, such as K_m and V_max, before the wide availability of powerful computers and non-linear regression software. The y-intercept of such a graph is equivalent to the inverse of V_max; the x-intercept of the graph represents −1/K_m. It also gives a quick, visual impression of the different forms of enzyme inhibition.

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,^[2] non-linear regression or alternative linear forms of the Michaelis–Menten equation such as the Hanes-Woolf plot or Eadie–Hofstee plot are generally used for the calculation of parameters.^[3]

When used for determining the type of enzyme inhibition, the Lineweaver–Burk plot can distinguish competitive, non-competitive and uncompetitive inhibitors. Competitive inhibitors have the same y-intercept as uninhibited enzyme (since V_max is unaffected by competitive inhibitors the inverse of V_max 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_m is unaffected) but different slopes and y-intercepts. Uncompetitive inhibition causes different intercepts on both the y- and x-axes .

Problems with the method

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.^[4]

References

^ Lineweaver, H and Burk, D. (1934). "The Determination of Enzyme Dissociation Constants". Journal of the American Chemical Society 56 (3): 658–666. doi:10.1021/ja01318a036.
^ Hayakawa, K.; Guo, L.; Terentyeva, E.A.; Li, X.K.; Kimura, H.; Hirano, M.; Yoshikawa, K.; Nagamine, T. et al. (2006). "Determination of specific activities and kinetic constants of biotinidase and lipoamidase in LEW rat and Lactobacillus casei (Shirota)". J Chromatogr B Analyt Technol Biomed Life Sci 844 (2): 240–50. doi:10.1016/j.jchromb.2006.07.006. PMID 16876490.
^ Greco, W. R. and Hakala, M. T., (1979). "Evaluation of methods for estimating the dissociation constant of tight binding enzyme inhibitors," (PDF). J. Biol. Chem. 254 (23): 12104–12109. PMID 500698.
^ Dowd, John E.; Riggs, Douglas S. (1965). "A Comparison of Estimates of Michaelis–Menten Kinetic Constants from Various Linear Transformations". J. Biol. Chem 240 (2): 863–869.

External links

NIH guide, enzyme assay development and analysis

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