Double reciprocal plots for

Figure 7.6 Double reciprocal plot for a tight binding competitive enzyme inhibitor, demonstrating the curvature of such plots. The dashed lines represent an attempt to fit the data at lower substrate concentrations to linear equations. This highlights how double reciprocal plots for tight binding inhibitors can be misleading, especially when data are collected only over a limited range of substrate concentrations.

A ratio used to assess the degree of cooperativity exhibited by an enzyme. It is equal to the true Ymax value (typically extrapolated from the high-substrate-concen-tration end of a double-reciprocal plot) divided by the apparent Emax value obtained from extrapolating the asymptote in the low-substrate-concentration portion of the double-reciprocal plot. For a noncooperative system, Ry will equal one positively cooperative systems will have values greater than one and negatively cooperative systems will have values less than one . This method requires good estimates of the asymptotes. 

Figure 9-12 Double reciprocal plots for two cases of noncompetitive inhibition.

Double-reciprocal plots for an ordered pathway. Measurements made at different fixed values of [S2] give a set of lines that intersect to the left of the ordinate. The two values of Km, Vm.ix and ATsl can be obtained by replotting the slopes and intercepts of these lines as functions of 1/[S2]. A random pathway gives similar results, but can be distinguished by making such measurements for the reverse reaction (Pi + P2 — Si + S2) in addition to the forward reaction. 

Using the Living Graphs for Equation 6-30 and the Lineweaver-Burk equation in Box 6-1, create Lineweaver-Burk (double-reciprocal) plots for all the cases in (a) and (b). When a = 2.0, does the x intercept move to the right or to the left If a = 2.0 and a = 3.0, does the x intercept move to the right or to the left ... 

B that is the double reciprocal plots for a ping-pong kinetic mechanism are parallel lines—the slopes are not changed by altering the concentration of the second substrate. 

Figure 4.3 Lineweaver-Burk, or double-reciprocal, plot for single-substrate irreversible Michaelis-Menten enzyme. A plot of 1/7 versus 1/[S] yields estimates of Vmax and Km, as illustrated in the figure.

Figure 4. Sorption of p-galactosidase by collagen preparations (samples as in Figure 2) at different degrees of lysine content as a double reciprocal plot for control, Ac — 14 X 10 6 for 15% modification, A0 — 0.53 X 10 6 for 30% modification, Ac = 0.41 X 10 6 for upper curve, A = 0.18 X 10 6 mol/g collagen,...

Fig. 7.4. Double reciprocal plot for reactions run using high substrate concentrations.

Fig. 7.6 shows the double reciprocal plots for reactions run in the presence of several concentrations of I. The series of lines intersecting the y-axis at the same point is the diagnostic pattern for the competitive inhibition of a reaction. As in the uninhibited reaction the y-axis intercept is lA max- This is the same for all values of [I] but the x-axis intercepts are the different values of-1/K vi(app) each concentration of I. The slopes of the lines are proportional to K]yi(app) which, as shown in Eqn. 7.27, also contains the term, K, the dissociation constant for the M-I complex. These slopes follow Eqn. 7.28,... 

Fig. 7.6. Double reciprocal plots for reactions run at different fixed concentrations of a competitive inhibitor, 1.

Fig. 7.14. Double reciprocal plots for ping-pong reactions run at several fixed concentrations of B.

In uncompetitive inhibition (f igure 8.21), the inhibitor combines only with the enzyme—substrate complex. The equation that describes the double-reciprocal plot for an uncompetitive inhibitor is... 

Figure 5.4 Patterns of double reciprocal plots for two substrate reactions, (a) Ping-pong. The double reciprocal plots for one substrate in the presence of fixed concentrations of the other are parallel, no matter which substrate reacts first, (b) Rapid equilibrium random, (c) Rapid equilibrium ordered, first binding substrate only.

Double reciprocal plots for an inhibited enzyme. The black line shows the double reciprocal plot for an enzyme in the absence of inhibitor. The other lines show the effect of an uncompetitive inhibitor (gray), a noncompetitive inhibitor (light purple), or a competitive inhibitor (purple). 

Figure 3. Double reciprocal plot for determination of polymer P-value (benzene, 6°C, 4 X I0"6M porphyrin sensitizer). For 1,4-polybutadiene, ordinate calculated from oxygen absorbed in 37 mL of solution in 95 min. For 1,4-polyisoprene, ordinate from oxygen absorbed in 40 mL of soltuion...

Fig. 11. Schematic double reciprocal plot for a 2-substrate reaction obeying Eqn. 16. The primary plot here is analogous to the Lineweaver-Burk plot for a 1-substrate reaction, but the and obtained from such a plot as the solid line here are apparent true only for the fixed value of [B] at...

Figure. 6.16. Double reciprocal plot for ping-pong mechanism.

Figure 6.10 Double-reciprocal plot for simple competitive inhibition...

Figure 3a. Double reciprocal plot for binding of C-atrazine in the presence of DCMU, lenacil, pyramin, propanil, RU 21731, and barban.

Double-reciprocal plot for increasing concentrations of an uncompetitive inhibitor ... 

Fig. 3.4 Lineweaver-Burke (double reciprocal) plot for the determination of kinetic parameters...

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