Microbiology and Immunology

Taq enzyme WORLD OF MICROBIOLOGY AND IMMUNOLOGY

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cells will initiate a rapid and strong immune response against

it. This is the reason why the body develops a permanent

immunity after an infectious disease.

Certain other cells known as the T-8 suppressor cells

play a role in turning off the immune response once the anti-

gen has been removed. This is one of the ways by which the

immune response is regulated.

See alsoBacteria and bacterial infection; Immune stimulation,

as a vaccine; Immunity, active, passive and delayed;

Immunity, cell mediated; Immunity, humoral regulation;

Immunochemistry; Immunological analysis techniques;

Immunology, nutritional aspects; Viruses and responses to

viral infection

TTaq enzymeAQ ENZYME

A taq enzyme is a bacterial enzyme that functions in the man-

ufacture of deoxyribonucleic acid(DNA). The ability of the

enzyme to function at higher temperatures than other similarly

functioning bacterial enzymeshas made it valuable in the

polymerase chain reaction.

The moniker taq denotes the origin of the enzyme. The

enzyme is produced by a bacterium known as Thermus aquati-

cus. This bacterium was discovered by Thomas Brock in the

mid 1970s in the nearly boiling waters of Mushroom pool, a

hot spring in Yellowstone National Park

Taq is a DNA polymerase. The enzyme manufactures a

strand of DNA that is complimentary to a single strand of

DNA. All bacteriapossess DNA polymerase. The reason that

the taq polymerase has become so significant to biotechnolog-

ical processes is because of the resistance of the enzyme to

heat. Amolecular biologytechnique known as the polymerase

chain reaction relies upon the exposure of DNA to heat in

order to separate the two strands of the double helix. Taq can

then use both of the single strands as templates for the manu-

facture of two new strands of DNA. To perform this function,

the polymerase is able to recognize the particular building

block, or nucleotide, on the DNA single strand and then posi-

tion a nucleotide that is the complimentary match to the par-

ticular target. Binding of the two nucleotides occurs. The

polymerase can then move on to the next nucleotide and the

process is repeated. When the DNA mixture is allowed to cool

the matching strands link together forming two double

stranded helices of DNA. If this process is repeated many

times, a huge number of copies of the target region of DNA

can be manufactured. The heat resistance of taq allows the

enzyme to function in the temperature conditions that keep the

DNA strands apart from each other. The DNA polymerase

Bison grazing near hot springs. Bacteria growing in hot springs are the source of taq.

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