Recombinant Human Taq protein

Taq recombinant protein, derived from the thermophilic bacterium *Thermus aquaticus*, is a heat-stable DNA polymerase widely used in polymerase chain reaction (PCR). Discovered in 1969 from hot spring microbial communities, *T. aquaticus* thrives at high temperatures, a trait linked to its enzyme thermostability. In 1988. researchers recognized Taq polymerase’s potential to automate PCR, as it withstands the cyclic high-temperature steps (∼95°C) required for DNA denaturation, unlike earlier heat-labile polymerases. This breakthrough revolutionized molecular biology by enabling rapid, efficient DNA amplification.

Recombinant Taq is produced via genetic engineering, where the *Taq* gene is cloned and expressed in *Escherichia coli*, ensuring high purity, scalability, and reduced batch variability compared to native enzyme extraction. The recombinant form retains key properties: optimal activity at 72°C, a half-life of 40 minutes at 95°C, and a polymerization rate of ∼1.000 nucleotides per minute. However, it lacks 3'→5' exonuclease proofreading activity, resulting in lower fidelity (error rate ∼10⁻⁴ per base) compared to high-fidelity polymerases. Despite this, its robust processivity and tolerance to PCR inhibitors make it ideal for routine amplification of DNA fragments up to 5 kb.

Taq’s applications span diagnostics, research, and biotechnology, including conventional PCR, DNA labeling, and sequencing. Its discovery underpinned the Human Genome Project and spurred the development of modified variants (e.g., Hot Start Taq) to enhance specificity. While newer enzymes address fidelity limitations, Taq remains a cornerstone in PCR due to its reliability, cost-effectiveness, and historical significance in advancing genetic research.