Reciprocal plots provide a relatively straightforward way to determine if an enzyme demonstrates Michaelis€“ Menten kinetics and to determine the corresponding kinetic parameters. However, the slope determined from these plots can require significant extrapolation to regions corresponding to low substrate concentrations. An alternative to the reciprocal plot is the Eadie€“Hofstee plot, where the reaction rate is plotted versus the rate divided by the substrate concentration and the data are fit to a straight line.

a. Beginning with the general expression for the reaction rate given by the Michaelis€“Menten mechanism:

Rearrange this equation to construct the following expression, which is the basis for the Eadie€“Hofstee plot

b. Using an Eadie€“Hofstee plot, determine R _max and K_m for hydrolysis of sugar by the enzyme invertase using the following data:

Sucrose]₀ (M)€¦€¦€¦€¦€¦€¦€¦€¦€¦€¦€¦€¦Rate (M s^€“1)

0.029€¦€¦€¦€¦€¦€¦€¦€¦€¦€¦€¦€¦€¦€¦€¦€¦.0.182

0.059€¦€¦€¦€¦€¦€¦€¦€¦€¦€¦€¦€¦€¦€¦€¦€¦.0.266

0.088€¦€¦€¦€¦€¦€¦€¦€¦€¦€¦€¦€¦€¦€¦€¦€¦.0.310

0.117€¦€¦€¦€¦€¦€¦€¦€¦€¦€¦€¦€¦€¦€¦€¦€¦.0.330

0.175€¦€¦€¦€¦€¦€¦€¦€¦€¦€¦€¦€¦€¦€¦€¦€¦.0.362

0.234€¦€¦€¦€¦€¦€¦€¦€¦€¦€¦€¦€¦€¦€¦€¦€¦.0.361

Transcribed Image Text:

Rmer[S]. Ro [S], + Km max