15N‐NMR spectroscopy. IV. Comparison of poly(L‐lysine) and isopoly(L‐lysine)
15N‐NMR spectroscopy. IV. Comparison of poly(L‐lysine) and isopoly(L‐lysine)
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15N-NMR 光谱 IV. 聚（L-赖氨酸）和同聚（L-赖氨酸）的比较。
DOI：
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发表时间：
1978
期刊：
影响因子：
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通讯作者：
M. Fehrle
中科院分区：
文献类型：
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作者：
W. Hull;H. Kricheldorf;M. Fehrle
用自然丰度15N-核磁共振波谱对水溶液中的异构体(L-赖氨酸)n和异构体(L-赖氨酸)n进行了表征。尽管两种聚合物的氨基在pH<；10时有几乎相同的位移，但在pH<；7时氨基氮相差5-6ppm，提供了一种容易识别的方法。此外，这些聚合物可以通过氨基的pKA和肽氮的碱性来区分。在pH 10.3和25°C下，(Lys)n表现出线宽和肽氮的前场化学位移，表明螺旋→螺旋转变。100%螺旋的形成可能产生高达5ppm的位移，这可能使15N-核磁共振谱更适合于这种转变的研究。
The natural abundance 15N‐nmr spectroscopy has been used to characterize the isomeric polymers (L‐Lys)n and iso (L‐Lys)n in aqueous solution. Although the peptide nitrogens of the two polymers have nearly equivalent shifts at pH < 10, the amino nitrogens differ by 5–6 ppm at pH < 7 and provide an easy means of identification. Furthermore, the polymers are distinguishable by the pKa of the amino group and the basicity of the peptide nitrogen. At pH 10.3 and 25°C, (Lys)n exhibits line broadening and an upfield chemical shift of the peptide nitrogen, indicative of the coil → helix transition. The formation of 100% helix may produce a shift as large as 5 ppm, which probably makes 15N‐nmr spectroscopy more suitable for studies of this transition.