Question

The kinetic data given below are for an enzyme in the absence and presence of a reversible inhibitor. From the data, generate both a Michaelis-Menten and Linweaver-Burk Plot for both that uninbibited and inhibited reactions. Graph both the uninhibited and inhibited data on the same plot. From these data calculate the Vmax and Km for the enzyme in absence and presence of the inhibitor. Is the inhibitor working cometitively or noncompetitively? Explain.

[S], mM Vo, mM/min   Vo, mM, min with inhibitor

0.5           23.5               16.67

1.0           32.2                25.25

1.5           36.9               30.49

2.5           41.8                37.07

3.5           44.0                38.91

Answer 1

[S], mM	1/S	Vo, mM/min	1/Vo	Vo, mM, min with inhibitor	1/Vo inh+
0.5	2.0	23.5	0.043	16.67	0.06
1	1.0	32.2	0.031	25.25	0.04
1.5	0.7	36.9	0.027	30.49	0.03
2.5	0.4	41.8	0.024	37.07	0.03
3.5	0.3	44	0.023	38.91	0.03

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The V_max remained constant but there is an increase in K_m when the inhibitor is present. This indicates a competetive inhibition