| Budget Amount *help |
¥3,800,000 (Direct Cost: ¥3,800,000)
Fiscal Year 1986: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 1985: ¥2,700,000 (Direct Cost: ¥2,700,000)
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| Research Abstract |
Recently, a number of lectins have been isolated from animal origins in addition to plants and microorganisms. The specificities of these lectins for glycoproteins and glycolipids have been extensively investigated, while only a little is known about the specificities for glycosaminoglycans. In this study, lectins highly reactive with glycosaminoglycans were specifically purified from adult chiken liver and the hemolymph of silkworm and Japanese horseshoe crab. The binding specificities of these lectins were extensively studied by hemagglutination inhibition assays and spectrophotometric analysis.
The lectin from adult chiken liver, which was named "DS-lectin" because of its high reactivity toward dermatan sulfate (DS), was purified by gel filtration on Toyopearl HW-55 and subsequent affinity chromatography on an immobilized heparin- or dermatan sulfate-column. Silkworm lectin was purified essentially by the same method. Horseshoe crab lectin was purified by affinity chromatography on N
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-acetyl-agarose. Upon interaction with specific saccharides, these lectins induced fluorescence difference spectra due to tryptophan residues. This permitted quantitative, sensitive and reproducible analysis of the interactions between the lectins and specific saccharides. The analysis gave quantitaive data on the interactions, i.e. the affinity constants of the lectins with low and high affinity saccharides, whereas hemagglutination inhibition assays gave only an approximate indication of the specificity of the lectins toward high affinity saccharides. The data obtained by the analysis indicated that three lectins have similar but significantly different specificities. Chiken liver and silkworm lectins have a high affinity for sugars having caboxyl groups, especially L-iduronic acid residues, in the glycosaminoglycans and no affinity for N-acetyl groups, while sulfate groups in the polysaccharides interfere with the specific binding to the lectins. On the other hand, horseshoe crab lectin has a high affinity for N-acetyl groups, a weak affinity for carboxyl groups and no affinity for sulfate groups in the glycosaminoglycans. Less
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