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In biochemistry, denaturation is a process in which proteins or nucleic acids lose folded structure present in their native state due to various factors, including application of some external stress or compound, such as a strong acid or base, a concentrated inorganic salt, an organic solvent (e.g., alcohol or chloroform), agitation and radiation, or heat. [3]
Enzyme denaturation is normally linked to temperatures above a species' normal level; as a result, enzymes from bacteria living in volcanic environments such as hot springs are prized by industrial users for their ability to function at high temperatures, allowing enzyme-catalysed reactions to be operated at a very high rate.
Nucleic acid thermodynamics is the study of how temperature affects the nucleic acid structure of double-stranded DNA (dsDNA). The melting temperature (T m) is defined as the temperature at which half of the DNA strands are in the random coil or single-stranded (ssDNA) state. T m depends on the length of the DNA molecule and its specific ...
Enzymes that catalyse this reaction are called deaminases. In the human body, deamination takes place primarily in the liver; however, it can also occur in the kidney. In situations of excess protein intake, deamination is used to break down amino acids for energy. The amino group is removed from the amino acid and converted to ammonia.
In the less extensive technique of equilibrium unfolding, the fractions of folded and unfolded molecules (denoted as and , respectively) are measured as the solution conditions are gradually changed from those favoring the native state to those favoring the unfolded state, e.g., by adding a denaturant such as guanidinium hydrochloride or urea.
Heat denaturation of DNA, also called melting, causes the double helix structure to unwind to form single stranded DNA. When DNA in solution is heated above its melting temperature (usually more than 80 °C), the double-stranded DNA unwinds to form single-stranded DNA. The bases become unstacked and can thus absorb more light.
Dideoxynucleotides are useful in the sequencing of DNA in combination with electrophoresis.A DNA sample that undergoes PCR (polymerase chain reaction) in a mixture containing all four deoxynucleotides and one dideoxynucleotide will produce strands of length equal to the position of each base of the type that complements the type having a dideoxynucleotide present.
The resulting apyrimidinic sites block replication by DNA polymerases, and are very labile to acid/base hydrolysis. Because UDG does not react with dTTP, and is also inactivated by heat denaturation prior to the actual PCR, carry-over contamination of PCRs can be controlled effectively if the contaminants contain uracils in place of thymines. [6]