$Taq$ Polymerase = Thermostable ($95^\circ\text{C}$ resistant), lacks $3' \to 5'$ proofreading exonuclease activity.
For high fidelity PCR, proofreading polymerases such as $Pfu$ are preferred.
Step 1: Understanding the Question:
The question asks about the primary enzymatic property of $Taq$ D polymerase that ebles its widespread utility in PCR reactions. Step 2: Key Formula or Approach:
PCR requires repeated cycling at high temperatures ($\sim 95^\circ\text{C}$) to deture double-stranded D template strands. Step 3: Detailed Explation:
• Origin of Taq Polymerase: $Taq$ D polymerase is isolated from the thermophilic bacterium Thermus aquaticus, which turally thrives in high-temperature hot springs.
• Thermostability Property: $Taq$ polymerase retains structural integrity and enzymatic activity at elevated temperatures, with an optimum activity at $72^\circ\text{C}$ and a half-life of over 40 minutes at $95^\circ\text{C}$. This thermostability elimites the need to add fresh enzyme after each deturation cycle.
• Lack of Proofreading: $Taq$ polymerase turally lacks $3' \to 5'$ proofreading exonuclease activity. As a result, it exhibits relatively low replication fidelity compared to proofreading polymerases like $Pfu$ or $Vent$.
• Template Specificity: $Taq$ is a D-dependent D polymerase, not an R-dependent enzyme (like reverse transcriptase). Step 4: Fil Answer:
The defining characteristic feature of $Taq$ polymerase is its high thermostability.
