碩士 / 國立臺灣海洋大學 / 食品科學系 / 106 / The purpose of this thesis phycobiliproteins (PBPs) are the major light-harvesting chromoproteins in some seaweeds, PBPs including phycoerythrin (PE), phycocyanin (PC) and allophycocyanin (APC). PE can be divided into four classes, based on their origin and absorption srectrum, includes R-PE (Rhodophyta), B-PE (Bangiales) and C-PE (Cyanophyta). Because R-PE could be used as a fluoredcent, it became more and more important in commercial sectors. But R-PE is susceptible to degradation by environmental factors, such as temperature, pH and light, leading to its degradation, thus limiting the application of R-PE. In this study, we purified R-PE from red alga Porphyra dentata, and increased R-PE stability via intramolecular crosslinking. R-PE was extracted by maceration in combination with ultrasonication. In biomass 5% extraction, the R-PE concentration and purity index (A565/280) achived 0.11 mg/mL, 0.88. Then, the extraction R-PE was purified by ion exchange chromatography and gel filtration. The purified R-PE showed absorption maxima at 565 nm, PI achieved was 1.48. Based on ESI-Q-TOF MS/MS result, the 20 kDa band on the SDS-PAGE was considered the α and β subunits. In this study, we used two crosslinker including glutaraldehyde (GA) and dithiobis succinimidyl propionate (DSP) to modify R-PE. GA and DSP could crosslink the primary amino group in the R-PE, in order to maintain the structure stability. The spectral analysis results showed the fluorescence intensity and A565 increased 40%, 75% after adding GA at a molar ratio 1: 5, and the fluorescence intensity increased 1.6 folds after adding DSP at a molar ratio 1:50. The U. V. absorption spectra results showed the maximum absorption was 495, 535, and 565 nm, and it was the same with native R-PE. On the thermal stability test, the R-PE, which was adding molar ratio 1:5 (R-PE/GA), incubated at 50°C for 20h. The result showed that A565 of R-PE treated with GA was decreased 44% but the control group was decreased 53%, and the fluorescence intensity increased 50% compared with the native R-PE. After treated at 50°C for 20h, the A565 could maintained 70% and the fluorescence intensity could also maintained 78% and 70% for the R-PE crosslink DSP with molar ratio 1:50 and 1:5. In conclusion, cross-linkers could provide additional covalent bonds in phycoerythrins to enhance the structural stability and decreasing the degradation of hydrophobic interactions between subunits due to high temperatures.
| Identifer | oai:union.ndltd.org:TW/106NTOU5253033 |
| Date | January 2018 |
| Creators | Tsao, Li-Ting, 曹立渟 |
| Contributors | Lin, Hong-Ting, 林泓廷 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 67 |
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