What effect did freezing have on amylase activity in the described experiment?

• A. Increased activity
• B. No effect
• C. Decreased activity
• D. Eliminated activity

Answer: (B)

Freezing acted only as a storage step and did not permanently alter the enzyme’s ability to catalyze starch breakdown under the assay conditions. Amylase activity depends on keeping the protein’s structure intact; if freezing is brief and the enzyme is thawed to the same conditions as the control, the active site remains functional. In this experiment, frozen samples showed essentially the same rate as unfrozen ones when tested at the same temperature, so there was no lasting effect from freezing. If freezing had damaged the enzyme, you’d expect a lower rate or loss of activity after thawing.