Physicochemical Properties and Oxidative Inactivation of Soluble Lectin from Water Buffalo (<Emphasis Type="Italic">Bubalus bubalis</Emphasis>) Brain |
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Authors: | Sabika Rizvi Naheed Banu |
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Institution: | (1) Department of Biochemistry, Faculty of Life Sciences, A.M. University, Aligarh, UP, 202002, India |
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Abstract: | Lectins are carbohydrate-binding proteins present in a wide variety of plants and animals, which serve various important physiological
functions. A soluble β-galactoside binding lectin has been isolated and purified to homogeneity from buffalo brain using ammonium
sulphate precipitation (40–70%) and gel permeation chromatography on Sephadex G50–80 column. The molecular weight of buffalo brain lectin (BBL) as determined by SDS-PAGE under reducing and non-reducing conditions
was 14.2 kDa, however, with gel filtration it was 28.5 kDa, revealing the dimeric form of protein. The neutral sugar content
of the soluble lectin was estimated to be 3.3%. The BBL showed highest affinity for lactose and other sugar moieties in glycosidic
form, suggesting it to be a β-galactoside binding lectin. The association constant for lactose binding as evidenced by Scatchard
analysis was 6.6 × 103 M−1 showing two carbohydrate binding sites per lectin molecule. A total inhibition of lectin activity was observed by denaturants
like guanidine HCl, thiourea and urea at 6 M concentration. The treatment of BBL with oxidizing agent destroyed its agglutination
activity, abolished its fluorescence, and shifted its UV absorption maxima from 282 to 250 nm. The effect of H2O2 was greatly prevented by lactose indicating that BBL is more stable in the presence of its specific ligand. The purified
lectin was investigated for its brain cell aggregation properties by testing its ability to agglutinate cells isolated from
buffalo and goat brains. Rate of aggregation of buffalo brain cells by purified protein was more than the goat brain cells.
The data from above study suggests that the isolated lectin may belong to the galectin-1 family but is glycosylated unlike
those purified till date. |
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Keywords: | Buffalo brain lectin Ammonium sulphate precipitation Gel filtration Oxidation Fluorescence UV spectra Equilibrium dialysis Brain cell aggregation |
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