半胱胺酸和酪胺酸水溶液的 213 nm 光分解量子產率
No Thumbnail Available
Date
2011
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
生物分子的單一掌性和生命的起源之間有著密不可分的關係，為了探討生物分子單一掌性形成的原因，本論文以自製的樣品槽腔體搭配雷射和傅立葉轉換紅外光光譜儀所組成的實驗系統對酪胺酸和半胱胺酸進行不對稱光分解現象的初步研究，並根據分子的圓二色光譜以及吸收光譜選擇適當的雷射波長做溶液態的光分解實驗。在我們以 213 nm 對樣品進行光分解，並藉由紅外光光譜獲得實驗分子濃度下降的資訊，經由計算得知實驗分子在溶液態的光分解量子產率。結果發現，根據半胱胺酸在紅外光光譜 1400、1351、1304 cm-1 面積和高度所得到的量子產率大部分為 20~40%，而酪氨酸以 1270 cm-1 面積和高度所得到的量子產率為 1%左右，我們認為是因為半胱胺酸能夠經由排斥態分解而酪胺酸無法經由排斥態分解造成量子產率有差異的原因。
The homochirality of biomolecule plays an important role on the origin of life. We studied the asymmetric photolysis of cysteine and tyrosine in aqueous solution using UV laser and FTIR. We measured the photodecomposition quantum yield at 213nm using FTIR. The results show that the quantum yields are very different for these two molecules. The quantum yields are 20~40% and 1% for cysteine and tyrosine, respectively. Cysteine is decomposed on a repulsive state which results in larger quantum yield. On the other hand, the repulsive state for tyrosine is changed in solution and the corresponding dissociation channel is quenched. As a result, the decomposition quantum yield of tyrosine is small.
The homochirality of biomolecule plays an important role on the origin of life. We studied the asymmetric photolysis of cysteine and tyrosine in aqueous solution using UV laser and FTIR. We measured the photodecomposition quantum yield at 213nm using FTIR. The results show that the quantum yields are very different for these two molecules. The quantum yields are 20~40% and 1% for cysteine and tyrosine, respectively. Cysteine is decomposed on a repulsive state which results in larger quantum yield. On the other hand, the repulsive state for tyrosine is changed in solution and the corresponding dissociation channel is quenched. As a result, the decomposition quantum yield of tyrosine is small.
Description
Keywords
半胱胺酸, 酪胺酸, 光分解量子產率