Ideal storage temperature for enzymes is typically:

• A. 2–8 C
• B. -20 C
• C. 25–30 C
• D. 10–15 C

Answer: (A)

Enzyme stability is best maintained by keeping the solution cool to slow down denaturation and degradation. Refrigeration at 2–8 °C slows chemical reactions and proteolytic processes that can inactivate enzymes, while keeping the preparation unfrozen so it remains readily usable when needed. Storing at room temperature (25–30 °C) allows rapid loss of activity as the protein can unfold or degrade faster, and a warmer range like 10–15 °C is less protective for routine use. While freezing at -20 °C can preserve enzymes for longer-term storage, it isn’t the typical choice for daily handling because repeated freeze–thaw cycles can reduce activity and require aliquoting. Hence, the standard practice is 2–8 °C.