While working in the lab, you forgot to keep enzymes back in the fridge. Which of the following enzyme
will be least affected on being left outside at room temperature?
1. Topoisomerase
2. Taq DNA polymerase
3. DNA ligase
4. BamHI restriction enzyme

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Which Enzyme Is Least Affected at Room Temperature?

If you’ve accidentally left your enzyme stock out on the lab bench, you’re probably wondering which one might still be usable. While most enzymes require cold storage to remain functional, Taq DNA polymerase is a major exception.

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What Makes Taq DNA Polymerase Special?

Taq polymerase is derived from the thermophilic bacterium Thermus aquaticus, which thrives in hot springs with temperatures around 70–80°C. Because of this, the enzyme:

• Is heat-stable

• Functions optimally at high temperatures (around 72°C)

• Remains active even after prolonged exposure to room temperature

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Why Other Enzymes Are Sensitive to Room Temperature

1. Topoisomerase

• Sensitive to denaturation at room temperature.

• Loses activity quickly without proper storage.

2. DNA Ligase

• Requires cold storage to maintain proper folding and function.

• Easily denatured, affecting ligation efficiency.

3. BamHI Restriction Enzyme

• A type II restriction enzyme.

• Very sensitive to temperature—typically stored at –20°C.

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Applications of Taq Polymerase in the Lab

• PCR (Polymerase Chain Reaction): A cornerstone enzyme for DNA amplification.

• Diagnostics: Used in COVID-19 and genetic disorder testing.

• Research: Fundamental in cloning and gene expression analysis.

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Conclusion

Among the enzymes listed, Taq DNA polymerase is the least affected by room temperature thanks to its thermostable nature. If you’ve left it out by mistake, chances are it’s still good to go