Polymeráza

Polymeráza is an enzyme that catalyzes the synthesis of nucleic acids by joining nucleotides into a growing polymer. In most cases, polymerázy extend a nascent strand by adding complementary nucleotides to a template, operating in the 5′ to 3′ direction. The reaction requires a primer or a pre-existing strand, a template, divalent metal ions (commonly Mg2+), and nucleotide triphosphates. Fidelity and processivity vary among different polymerázy, and some possess proofreading activity to correct misincorporated nucleotides.

There are several major classes of polymerázy. DNA polymerázy synthesize DNA and play essential roles in replication, repair, and recombination. In bacteria, DNA polymeráza III is the primary replicative enzyme, while DNA polymeráza I participates in processing Okazaki fragments; in eukaryotes, multiple polymerázy (such as alpha, delta, and epsilon) coordinate genome duplication, with polymeráza gamma handling mitochondrial DNA. RNA polymerázy synthesize RNA from a DNA template in transcription; eukaryotes have three main nuclear RNA polymerázy (I, II, III) with distinct gene sets. Reverse transcriptázy are RNA-dependent DNA polymerázy used by retroviruses and in molecular biology to convert RNA into complementary DNA (cDNA) for research.

Polymérases are central to many biotechnological techniques, including polymerase chain reaction (PCR), DNA sequencing, and cloning. Their properties—such as speed, fidelity, and primer dependence—determine their suitability for a given application. Understanding polymerázy function helps explain how genetic information is copied, expressed, and manipulated in both natural and laboratory settings.