Extraction and Purification of a Lectin from Red Kidney Bean and Preliminary Immune Function Studies of the Lectin and Four Chinese Herbal Polysaccharides

Yufang Hou,Liu Yanyan,Yubao Hou,Jichang Li,Guang Qin

doi:10.1155/2010/217342

Yufang Hou, Liu Yanyan + Show 3 more

Open Access

https://doi.org/10.1155/2010/217342

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Abstract

Reversed micelles were used to extract lectin from red kidney beans and factors affecting reverse micellar systems (pH value, ionic strength and extraction time) were studied. The optimal conditions were extraction at pH 4–6, back extraction at pH 9–11, ion strength at 0.15 M NaCl, extraction for 4–6 minutes and back extraction for 8 minutes. The reverse micellar system was compared with traditional extraction methods and demonstrated to be a time-saving method for the extraction of red kidney bean lectin. Mitogenic activity of the lectin was reasonably good compared with commercial phytohemagglutinin (extracted from Phaseolus vulgaris) Mitogenic properties of the lectin were enhanced when four Chinese herbal polysaccharides were applied concurrently, among which 50 μg/mL Astragalus mongholicus polysaccharides (APS) with 12.5 μg/mL red kidney bean lectin yielded the highest mitogenic activity and 100 mg/kg/bw APS with 12.5 mg/kg/bw red kidney bean lectin elevated mouse nonspecific immunity.

Highlights

Lectins are carbohydrate-binding proteins, which are highly variable in their amino acid sequences, widely distributed in microorganisms, viruses, animals and higher plants [1], and with different functions, structures, tissue localizations and carbohydrate-binding specificities
Plant lectins were classified into seven families according to their evolutionary and structural characteristics by Van Damme et al [2], one of which is the legume lectin family
The highest lectin concentration was obtained with an extraction time of 4–6 minutes, beyond which the extraction rate decreased greatly, while the back extraction rate increased as the extraction time increased, but did not increase any further after 8 minutes extraction (Figure 1(b))

Summary

Introduction

Lectins are carbohydrate-binding proteins, which are highly variable in their amino acid sequences, widely distributed in microorganisms, viruses, animals and higher plants [1], and with different functions, structures, tissue localizations and carbohydrate-binding specificities. A number of diverse physiological roles have been proposed for these proteins, including mitogenic [5, 6], antifungal [7], antiviral [8, 9], anti-insect [10, 11], and antitumor [6, 12,13,14,15] activities. Lectin extraction is usually achieved using different methods of diffusion in aqueous solution and ammonium sulfate precipitation Problems with these methods include cumbersome operations, a low extraction rate, hard to extract hand-running and amplify, which universally exist in the separation and purification of biomolecules. Mitogenic activity of red kidney bean lectin and four Chinese herbal polysaccharides (CHPs) were applied together to detect if the immunomodulatory activities were enhanced

Materials and Methods

Traditional Methods

Results

Discussion