Faculty of Physics and Mathematics, Ilia Chavchavadze State University, Chavchavadze Ave. 32, 0179 Tbilisi, Georgia.
Ecotoxicol Environ Saf. 2010 Mar;73(3):448-55. doi: 10.1016/j.ecoenv.2009.12.005. Epub 2009 Dec 29.
The influence of deleterious UV radiation on collagen molecules in the absence and presence of ascorbic acid using UV-vis and FT-IR spectroscopy has been studied. Intensity of UV-vis absorption spectrum of collagen with a maximum at 275 m due to the aromatic residues (tyrosine and phenylalanine) increases with the increasing dose of UV radiation. This effect is significantly hindered in the presence of antioxidant ascorbic acid. Intensities of FT-IR bands (amide A, B, I and II) of collagen decrease with the increase of the UV radiation dosage. Intensities of bands are also decreased in the presence of ascorbic acid. Results suggest that increasing the concentration of ascorbic acid increases the photo-stability of collagen, and the collagen becomes less sensitive to UV radiation. It is possible that hydrogen bonds form between the groups N-H of collagen and C=O of ascorbic acid. It is believed that under UV radiation free radicals appear in acid soluble collagen and resulting in photodegradation of the macromolecule restore due to the ability of ascorbic acid donating one or two electrons. Increasing the dose of radiation causes more molecules of ascorbic acid to slow down, and their antioxidant effect is diminished accordingly.
已经研究了在缺乏和存在抗坏血酸的情况下，有害的紫外线辐射对胶原蛋白分子的影响，使用了 UV-vis 和 FT-IR 光谱。由于芳香族残基（酪氨酸和苯丙氨酸）而在 275 m 处具有最大吸收峰的胶原蛋白的紫外可见吸收光谱的强度随着紫外线辐射剂量的增加而增加。在抗氧化剂抗坏血酸存在下，这种效应受到显著阻碍。胶原蛋白的 FT-IR 带（酰胺 A、B、I 和 II）的强度随紫外线辐射剂量的增加而降低。在抗坏血酸存在下，带的强度也降低。结果表明，增加抗坏血酸的浓度会增加胶原蛋白的光稳定性，使胶原蛋白对紫外线辐射的敏感性降低。可能是胶原蛋白的 N-H 基团和抗坏血酸的 C=O 基团之间形成氢键。据信，在紫外线辐射下，游离基出现在酸溶性胶原蛋白中，导致由于抗坏血酸具有提供一个或两个电子的能力，大分子发生光降解还原。辐射剂量的增加会导致更多的抗坏血酸分子减缓，因此其抗氧化作用相应减弱。
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