Storing ALP at 4°C has what effect on measured activity?

• A. True increase
• B. False increase
• C. No change
• D. Decrease

Answer: (B)

Enzyme activity is highly dependent on temperature; lowering the temperature slows the catalytic rate. Storing ALP at 4°C reduces molecular motion and slows the enzyme’s reaction rate, so the measured activity after storage is not increased. In fact, it is more likely to be preserved only temporarily or to decline with time, depending on how long and under what conditions it’s stored. So the idea that storage at 4°C would increase activity is not correct; the observed effect would be “not increased” (and often a decrease with continued storage). For best results, measure promptly after collection or store under appropriate conditions to minimize activity loss.