Question

During the early stages of an enzyme purification protocol, when cells have been lysed, but cytocolic components have not been separated, the reaction velocity vs. [S] is sigmoidal. As you continue to purify the enzyme, the curve becomes hyperbolic. Explain this result.

A This is an enzyme that displays Michaelis-Menten kinetics and you are purifying away an inhibitor.

B This is an enzyme that displays Michaelis-Menten kinetics, but you must use a double-reciprocal plot to determine Vmax and KM correctly.

C This is an allosteric enzyme, but you must use a double-reciprocal plot to determine Vmax and KM correctly.

D This is an allosteric enzyme. During purification, you purify away an effector.

E This is an allosteric enzyme, displaying a double displacement mechanism. During purification, you purify away one of the substrates.

(please explain the answer)

Answer 1

Ans - the correct answer is that is is an allosteric enzyme . During purification you purify away an effector.

It is because, since it was showing a sigmoidal curve, it is an characteristic property of allosteric enzymes. As enzymes who follow Michelle's menten equation , they show hyperbolic curve in the beginning.

Now, allosteric enzyme have multiple binding site, which causes it to deviate from michles menten and presence of an effector change the binding capacity of the enzyme, due to this change the enzyme did not follow it's normal path, but deviate from it and turn to hyperbolic.