碩士 / 國立臺灣大學 / 海洋研究所 / 91 / Abstract
Lectins, with wide distribution in nature, have been known to be proteins or glycoproteins. They specifically recognize and bind some carbohydrates, resulting in agglutination of cells of various forms. Therefore, they are agglutinins. In this study a lectin has been extracted, purified and characterized from the marine red alga Hypnea japonica Tanaka. The lectin (HJL) was extracted by PBS containing 50 mM lactose and precipitated with 20 ~ 60% saturated ammonium sulfate, followed by purification by affinity chromatography on Sepharose CL-4B column. The purified protein was a glycoprotein with a molecular weight of 42 kDa. It contained 50% carbohydrate. The protein was mainly composed of glycine, glutamic, aspartic and serine residues. Methionine and histidine were also present in HJL in a minor portion. Notably, HJL had the property of self-aggregation, to form large protein clusters. It agglutinated human ABO erythrocytes as well as rabbit and duck erythrocytes, and the activity increased markedly towards protease-treated human erythrocytes. However, hemagglutination reaction was strongly inhibited by polysaccharides (agarose and carrageenan) and glycoproteins (mucin and asialofetuin). Galactose and lactose were also inhibitory to the activity, but to a lesser extent. The hemagglutinating activity of HJL was stable at 40 ~ 70℃ incubation for 1 hr and independent of divalent cations, but abolished in pure water. Additionally, the activity was stable in a wide range of pH from 2.0 ~ 10.0, with the optimum pH for binding affinity at 5.0 ~ 7.0.
| Identifer | oai:union.ndltd.org:TW/091NTU00279029 |
| Date | January 2003 |
| Creators | Kuan-Yu Chen, 陳冠佑 |
| Contributors | Rang Huang, Woan-Ru Liao, 黃穰, 廖婉茹 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 66 |
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