Polimeráz

Polimeráz refers to enzymes that catalyze the synthesis of nucleic acids by adding nucleotides to a growing chain using a nucleic acid template. They are essential for DNA replication, DNA repair, transcription, and RNA synthesis. Major classes include DNA polymerases, RNA polymerases, and reverse transcriptases.

DNA polymerases replicate genomes by extending primers in the 5' to 3' direction. In bacteria, DNA polymerase III is the main replicative enzyme, while DNA polymerase I removes RNA primers and participates in repair. In eukaryotes, the main replicative enzymes are DNA polymerases α, δ, and ε.

RNA polymerases synthesize RNA from a DNA template. Bacterial RNA polymerase is a single multi-subunit enzyme. Eukaryotes have three nuclear RNA polymerases (I, II, III) that transcribe rRNA, mRNA, tRNA, and other non-coding RNAs. Transcription requires promoter recognition and accessory factors.

Reverse transcriptases synthesize DNA from RNA templates and are essential for retroviruses and many biotechnological methods, such as RT-PCR. They typically lack proofreading, though high-fidelity variants exist.

Polimeráz enzymes are central to biotechnology, enabling methods like PCR, DNA sequencing, and cloning. The development of thermostable DNA polymerases, such as Taq polymerase, enabled rapid amplification of DNA, while engineered polymerases expand fidelity and substrate range for diverse applications.

Historically, the first DNA polymerase to be purified and characterized was DNA polymerase I from Escherichia coli, described by Arthur Kornberg in 1956. Since then, numerous polymerases across life domains have been identified and categorized into several families.