Question

A very potent inhibitor of chucknorrisase is bruceleeumate. The inhibition is marked by only intercept effects in the double reciprocal plot. The intercept inhibition constant is 8.00 nM. If 36.0 nM inhibitor was used in a study, what would the resulting intercept be for the Lineweaver-Burke plot in the presence of 8.00 nM inhibitor. The linear fit of the Lineweaver-Burke plot of the kinetics study done in the absence of inhibitor is y = 71.5 x + 999. The study with the inhibitor was done with the same conditions.

2.000 x 10-4

2.435 x 10-4

4995

357.5

4107

Answer 1

since the slope in the presence and absence of inhibitor remain the same, it is the case of uncompetitive inhibition where the slope is Kmapp/Vmax app for inhibition , KM/Vmax is slope for no inhibtion, 1/Vmax is intercept for no inhibition and 1/Vmax app is intercept with inhibition.

The reciprocal plot is 1/V= (KM/Vmax)*1/S + 1/Vmax for no inhibition,

the plot of 1/V vs 1/S is straight line whose intercept is 1/Vmax= 999, Vmax= 1/999 =0.001nm/sec

the relation between Vmax and and Vmaxapp for inhibition of this type is

1/Vmaxapp= (1+I/KI)/Vmax

Ki= 8 nM and I= 36 nM

1/Vmaxapp = (1+I/KI)/Vmax=(1+36/8)*999

Vmaxapp= 2*10-4, the intercept ini the presence of inhibitor. A is correct.