Comparison of Biochemical Characterization of Korean and Chinese Mung Bean Lectin

Abstract

The lectins were separated from Korean and Chinese mung bean seeds finally via chromatography using Sephadex G-100 and their biochemical features were studied and compared. They showed no hemagglutination with human red blood cells regardless of trypsin treatment and showed hemagglutination with only trypsin treated rabbit red blood cells. The molecular weights of two lectins were identified as 54 kDa and 28 kDa by SDS-PAGE. It was found that while the optimal reaction temperature of the lectin from Korean mung bean was 60℃, that of the lectin from Chinese mung bean seeds was 50℃. It was found also that the most thermal stable temperature of the seed lectin from Korean mung bean seeds was 50℃ and the lectin from Chinese mung bean was 40-50℃. The lectin from Korean mung bean seeds showed the highest activity at pH 3.2 and the lectin from Chinese mung bean showed the highest activity at pH 6.2. It was identified that when treating a denaturant, thiourea and guanidine-HCl resulted in no hemagglutination, so they induced denaturalization. It was identified also that there was no hemagglutination with urea, so it did not induced denaturalization. They showed no septicity to 6 types of carbohydrates including D-glucose. In addition, the lectins from the two mung bean seed had specificity to metal ions.Key words : Biochemical characterization, Korean and Chinese mung bean seed, lectin *Corresponding author *Tel : +82-53-580-5207, Fax : +82-53-580-5164 *E-mail : rks@kmu.ac.kr This is an Open-Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. IntroductionMung bean (Phaseolus radiatus L. var.) is an annual plant which belongs to Leguminosae and is originated from India and cultivated also in Korea. Length of its stem is 60~80 cm and brown pili are spread on the whole of plant. Its pod is 5~6 cm in length, has slender and long shape with rough pili and projections, and contains 10-15 fruits. As it is highly nutritious, containing about 60% of starch and 21% of protein as main ingredients, it serves an important nutrition source to animals as well as humans and is also used as a major protein source due to its higher fiber content and lower fat content [28].Lectin is one of natural proteins cohering reversibly to specific monosaccharide and polysaccharide and has specific binding affinity to carbohydrates [30] It is widely distributed across plants, animals and microorganisms in nature [26]. Plant lectin is mainly isolated from dried seeds, but exists also in leaves, stems, roots, and tubers [39]. Particularly it is rich in seeds of leguminous plants among them [5,27].The lectin is synthesized in ribosome of plant cells, transferred to secretion system in form of glycoprotein, accumulated highly in vacuoles and cell walls [6], and then used in growth of young plants. In additions it serves...