catalyzed reaction

Question

You are analyzing a reaction catalyzed by an enzyme which functions at a pH of 9.0 and a temperature of 37C. You conduct the reaction at a pH of 3.0 and observe that the enzyme does not function. The enzyme activity is restored if the pH is reverted back to 9.0. What level of the enzyme structure is not altered by the pH change?

A)Primary

B)Helical secondary

C)Beta pleated sheet

D)Tertiary

Answer 1

Since the enzyme was rendered inactive at pH 3.0 but was able to function when the pH returned to 9.0 means that the amino acid chain (primary structure) was unaltered by the pH change. The coiling and folding (secondary and tertiary structures) were altered and that's why it didn't work.