Plotting Direct Linear Plot Kinetics

The direct linear plot technique is described by Eisenthal and Cornish-Bowden 9, and the methods for obtaining con fidence limits by Porter and Trager 14. The modification given by Cornish-Bowden and Eisenthal 6 of treating negative estimates in the third quadrant as very large positive numbers is used for both the estimates and the

A new plot is described for analysing the results of kinetic experiments in which the Michaelis-Menten equation is obeyed. Observations are plotted as lines in parameter space, instead of points in observation space. The direct linear plot. A new graphical procedure for estimating enzyme kinetic parameters Biochem J. 1974 Jun1393715-20

B- The direct linear plot. In enzyme kinetics V max is the maximum rate of the enzymatic reaction. For drug metabolism in vivo, V max is the maximum rate of drug metabolism by a specific pathway.V max has units of amount per time and can also have units of concentration per time.

VKm. The direct linear plot distinguishes between these twocases in averystraightforward manner if plots are madeat various values of i, the common intersectionpointshifts parallel withtheKmaxisand awayfromthe Vaxisasiis increased,iftheinhibition is competitive, but directly towards the origin if the inhibition is uncompetitive. These two

This is also the case for non-linear plots, such as that of against , often wrongly called a quotMichaelis-Menten plotquot, and that of against used by Michaelis and Menten. 6 In contrast to all of these, the direct linear plot is a plot in parameter space , with observations represented by lines rather than as points.

Figure 3. Two graph pages are produced by Exploratory Enzyme Kinetics. A - the direct linear and Michaelis-Menten plots. B - the two secondary plots. These plots strongly suggest mixed inhibition since the medians progress diagonally down and to the right in the direct linear plot. Also, straight lines fit the secondary plots data very well. The

A direct linear plot of the data from Table 17.1 is plotted, for example, Instead, other kinetic models should be explored to address deviations from hyperbolic kinetics. Nonlinear Lineweaver-Burk plots result if multiple enzyme forms acting on the same substrate isozymes with distinct kinetic characteristics exist in the assay. With

affect the plots. A comparison between the two graphic representations direct is illustrated here with two quotbadquot data points see Fig. 8.16, WWBH. The same data points are plotted on adjacent Lineweaver-Burk in the left graph of this figure. Two features of the direct linear plot are immediately evident by comparison.

The kinetics of enzyme-catalyzed reactions with two or more substrates or products. Eisenthal R. Statistical considerations in the estimation of enzyme kinetic parameters by the direct linear plot andother methods. Biochem J. 1974 Jun1393721-730. doi 10.1042bj1390721. HOFSTEE B. H. Non-inverted versus inverted plots in enzyme

The Direct Linear Plot The direct linear plot is the basis of the Exploratory EK macro. It is described in the text by Cornish-Bowden 1 and in his and Eisenthal's papers 2-4. It is an excellent first-step for enzyme kinetics analysis since it examines the validity of the Michaelis-Menten assumption. It also gives