Question

Why cant we use dna polymerase isolated from bacteria living at 37degree c?

Answer 1

You want to maintain a high enzymatic activity in your Taq stock solution. If stored at room temperature your stock solution would lose activity much faster compared to deep-frozen storage. True, Taq is subject to high temperatures during PCR but here you use the enzyme and discard it subsequently when you purify the amplification product(s).

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