英国论文迟交：DNA的聚合链的吸光性
英国论文迟交：DNA的聚合链的吸光性
血红素组的一些蛋白辅因子在可见范围内表现出吸光度。在肽基和芳香残基的情况下，它们被发现是不对称结构的一部分。它们在类似于折叠蛋白的不对称环境中被固定。有偏振光，被发现被吸收在不同的程度之间的左和右手组。这也被称为循环二色性。这可以在蛋白质的紫外光谱中看到。在核酸的情况下，在240到275纳米区域之间有很强的光吸收。在碱基的嘧啶和嘌呤环系统中观察到一个跃迁。它们对pH敏感。在中性pH条件下，鸟苷的最大吸收范围为253 nm到胞苷的271 nm。
这表明DNA的聚合链在260纳米左右对光有很强的吸收能力。在核酸的情况下，当化合物的DNA在高温下从双键分离成单键时，就认为发生了变性。在聚合链反应中观察到这一过程。当双链DNA变成单链DNA就被认为是变性的。DNA的碱基堆积在双螺旋结构的强疏水性核内。与单链DNA相比，吸光度降低。这在寡核苷酸的情况下被发现更加相关。这种现象的DNA被定义为低色度。这是用来熔化DNA和双螺旋。
英国论文迟交：DNA的聚合链的吸光性
Some of the protein cofactors of the heme groups are found to show absorbance in the visible range. In the case of the peptide groups and aromatic residues they are found to be a part of the asymmetric structure. They are immobilized in the asymmetric environment similar to the folded proteins. There are the polarized lights that are found to be absorbed in different extents between the left and the right handed groups. This is also known as circular dichroism. This is seen in the UV spectrum of proteins. In the case of nucleic acids there is a strong absorbance of the light between the regions of 240 to 275 nm. There is a transition that is observed in the pyrimidine and the purine ring systems of the nucleobases. These are sensitive to the pH. In the case of neutral pH the absorption maxima range is found to be between 253 nm (in the guanosine) to 271 nm (in the cytidine).
This shows that the polymeric chains of the DNA have a strong absorbance towards the light at around 260 nm. In the case of the nucleic acid the denaturation is considered to occur when the DNA of the compound in the case of high temperatures becomes separated from double bonds to single bonds. This process is observed during the polymerization chain reaction. When the double stranded DNA becomes a single stranded then the DNA is considered to be denatured. DNA has the bases stacked in a strong hydrophobic core of the double helix structure. The absorbance is considered to be decreased when compared to the single stranded DNA. This is found to be even more relevant in the case of oligonucleotides. This phenomenon of the DNA is defined as hypochromism. This is used for the melting of the DNA and the double helices.
