Q: About Michaellis Constant (Km)

Enzyme Question No.10 (E-10)



The measuring of the Km in an isomerase that catalyzes the transformation of different D-carbohydrates in the corresponding L- isomers,  show different values, depending on the carbohydrate that is transformed. Given the following carbohydrates  with the corresponding values of Km, mark the one for which the enzyme show less affinity:


a) D-glucose                    Km =  2000 uM


b) D-galactose                Km =   4500 uM


c) D-mannose                Km =  8000 uM


d) D-Ribose                    Km = 10000 uM


e) D-fructose                   Km =  9000 uM



3 thoughts on “Q: About Michaellis Constant (Km)

  1. Enzyme Kinetics program

    This program is a useful tool for anyone involved in studying enzyme kinetics. This program calculates the Michaelis constant Km, the limiting velocity Vmax, and the inhibition constant Ki for the rate of catalysis by enzymes. These calculations are based on the Michaelis-Menton equation. Just enter the inhibition concentration [I], the initial velocities Vo, and the substrate concentrations [S] for each reaction. Select the type of plot you want (e.g., Lineweaver-Burk), and the program will calculate the Michaelis constants Km and limiting velocities Vmax for you. From the graph of the Lineweaver-Burk plot, you can determine the type of inhibition in your experiment. This information is used to select the appropriate type of plot needed to calculate the inhibition constant Ki. This program will increase your productivity by performing those tedious enzyme kinetics calculations.

    • scratch that, the highest affinity is a high Km because Km= the concentration of the substrate times the concentration of the enzyme, over the concentration of the substrate enzyme complex. so the least affinity would be D, because it has the largest Km.

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