Inhibition of Fumarase by Succinate

The enzyme fumarase catalyzes the hydration of fumarate to malate. This enzyme is known to be reversibly inhibited by succinate. Reaction velocities were determined in triplicate at different substrate concentrations, in 

The Michaelis-Menten model was fitted to the experimental data using standard nonlinear regression techniques to obtain estimates of and K (Fig. 4.1). Best-fit values of and K of corresponding standard errors of the estimates plus the number of values used in the calculation of the standard error, and of the goodness-of-fit statistic are reported in Table 4.3. These results suggest that succinate is a competitive inhibitor of fumarase. This prediction is based on the observed apparent increase in Ks in the absence of changes in Vmax (see Table 4.1). At this point, however, the experimenter cannot state with any certainty whether the observed apparent increase in Ks is a tme effect of the inhibitor or merely an act of chance. A proper statistical analysis has to be carried out. For the comparison of two values, a two-tailed t-test is appropriate. When more than two values are compared, a one-way analysis of variance (ANOVA), 

TABLE 4.2 Rate of Hydration of Fumarate to Malate by Fumarase at various Substrate Concentrations  

TABLE 4.3 Estimates of the Catalytic Parameters for the Fumarase-Catalyzed hydration of Fumarate to Malate  

Having established that succinate acts as a competitive inhibitor, it is possible to determine the value of a  

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