Purification and characterization of the agglutinin from Gracilaria eucheumoides
| Autor: | Chia-Chun Chung, 鍾佳君 |
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| Rok vydání: | 2003 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 91 The hemagglutinating activity of marine algae collected from Audi of northeastern coast, Shanyuan of eastern coast, Maobito of southern coast of Taiwan and Kuapi of Penghu islands was investigated. In addition, the agglutinin of the marine red alga Gracilaria eucheumoides was extracted, purified and then characterized biochemically. The results indicated that extracts of 80% of the total assayed species exhibited agglutinating activity against human native erythrocytes, and the red algae had higher percentage of species showing positive reaction than that of green or brown algae. Noticeably, agglutinating activity of marine algae varied significantly with season and sampling locality. Pretreatment of erythrocytes with proteases, i.e. trypsin, pronase and papain, could improve the detection of agglutinins in most of the marine algae assayed. The agglutinin of G. eucheumoides was purified using gel filtration and ion exchange column chromatography. The purified protein had an apparent molecular weight of 61 kDa based on both SDS-PAGE and gel filtration. It was a monomer, containing 11% carbohydrate moiety. Therefore, the purified agglutinin was a novel glycoprotien, designated Gracilaria eucheumoides agglutinin (GEA). GEA was able to react strongly with human and animal native erythrocytes. In addition, it had strong binding affinity for glycoproteins, i.e. BSA, mucin, ovalbuin, yeast mannan, asialofetuin and fetuin, but not for the monosaccharides tested, except D(+)mannose and GalNAc. The agglutinating activity of GEA was stable over a wide range of pH (3-10), tolerant to relatively high temperature, i.e. 80-95 ℃, and independent on the presence of divalent cations. The amino acid composition was rich in glutamic acid, glycine, aspartic acid and serine, and showed high contents of acidic amino acids and a low content of basic amino acids. GEA also had antibiotic activity against the marine vibrio Vibrio harveyi. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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