For which one of the following enzyme activity plots, will the K_m of the enzyme for substrate 'S' be 20? [S] indicates substrate concentration.

Step-by-step solution

The Michaelis constant ( K_m ) is defined as the substrate concentration [S] at which the reaction velocity ( V ) is half of its maximum velocity ( V_ max ). From the given plots, the maximum velocity is indicated by the dashed line: V_ max = 16 Therefore, half of the maximum velocity is: V_ max 2 = 16 2 = 8 We need to find the plot where the velocity is 8 when the substrate concentration [S] is 20 . Looking at the given options: In plot (a), the curve passes exactly through the point (20, 8) . This means at [S] =