Overview of polymerase chain reaction, what is polymerase chain reaction?

Polymerase chain reaction (PCR) is a million-fold (106 109) amplification of a very small amount of a specific nucleic acid in a short period of time in a test tube, so it is also known as gene amplification technology, and its sensitivity far exceeds that of all serological tests, including radioimmunoassay. It is currently the world's most advanced technology for the study of early diagnosis of infectious diseases and hereditary diseases, genetic detection of cancer cells, and gene mutations. Hepatitis B virus and hepatitis C and E viruses can be detected in very small amounts in patients.

However, because it is too sensitive, it is also prone to false positives due to contamination of specimens.

DNA polymerase takes deoxynucleotide triphosphates (DATP, DCTP, DGTP, or DTTP, collectively referred to as DNTPS) as the object of action, and the action period is the DNA replication period.

Helicase targets the hydrogen bonds of the DNA double-strand, and the period of action is the period of DNA or RNA replication.

RNA polymerase targets four ribonucleotide triphosphates (NTP: ATP, GTP, CTP, UTP) in the transcriptional phase.

The basic principle of polymerase chain reaction (PCR) is an enzymatic synthesis reaction. That is, in the presence of template DNA, primers and deoxyribonucleotides, the DNA strand is amplified and extended under the action of DNA polymerase.

In the experiment, the hydrogen chain of the DNA double helix was broken and dissociated into single-stranded DNA by heating and denatured. Then, by annealing, abrupt cooling causes the primers to form hybridized strands locally with their complementary templates; Then, in the presence of DNA polymerase, deoxyribonucleoside triphosphate substrate and magnesium ions, the DNA strand is extended with primers as the starting point under the catalysis of polymerase.

Extended information: PCR (polymerase chain reaction) is the use of DNA in vitro at a high temperature of 95 °C will be denatured into a single strand, at low temperature (often around 60 °C) primers and single strands according to the principle of base complementarity, and then adjust the temperature to the optimal reaction temperature of DNA polymerase (about 72 °C), DNA polymerase along the phosphoric acid to the five-carbon sugar (5'-3') in the direction of the synthesis of complementary chains. The polymerase-based PCR machine is actually a temperature-controlled device, which can be well controlled between the denaturation temperature, the refolding temperature, and the extension temperature.

Reaction characteristics: strong specificity;

High sensitivity; Easy and fast;

Low purity requirements.