Understanding Enzyme Z Kinetics and Inhibition

Very Hard Biochemistry Enzymes

In a laboratory setting, researchers are investigating the catalytic efficiency of a particular enzyme, enzyme Z, which catalyzes the conversion of substrate A to product B. Initial studies indicate that the reaction follows Michaelis-Menten kinetics. Based on this model, the researchers measure the reaction rates at varying concentrations of substrate A. They observe that an increase in substrate concentration results in an increase in the reaction rate, but after a certain concentration, the rate levels off.

Further analysis reveals that the enzyme Z has a maximum velocity (V_max) of 100 µmol/min when substrate concentration is sufficiently high. The concentration of substrate A required to reach half of V_max is determined to be 10 µM, indicating the Michaelis-Menten constant (K_M) for enzyme Z is 10 µM. During another experiment, enzyme Z is found to have a lower activity in the presence of an inhibitor that competes with substrate A for the active site.

Based on this information, which of the following statements is true regarding enzyme Z?

Enzyme Z exhibits cooperative binding, as indicated by the sigmoidal curve of the reaction rate.

Inhibition observed is indicative of non-competitive inhibition affecting the Vmax.

The KM value of 10 µM suggests high affinity of enzyme Z for substrate A.

At substrate concentrations much higher than 10 µM, the reaction rate approaches Vmax and is independent of substrate concentration.

Hint

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