A novel yeast-binding lectin from hemolymph Cyclina sinensis (Gmelin) and its effects on yeast cells

Purification and Characterization of a New Lectin from Loach Skin Mucus

Lectin from loach skin mucus plays an important role in pathogen defense. However, hardly can any paper relevant to the character of lectin from loach skin mucus be found in recent years. In this study, a kind of new lectin (LML), with a high hemagglutination activity of 166.23 × 103 HU/mg, was successfully isolated and purified from loach skin mucus. LML was a kind of glycoprotein with a molecular weight of 245 kDa. Also, the monosaccharide composition suggested that its carbohydrate chain was composed of rhamnose, arabinose, xylose, mannose, glucose, and galactose with a molar ratio of 2.02 : 11.66 : 2.06 : 1.00 : 14.09 : 6.00. Besides, LML depended on Ca2+to induce hemagglutination and was strongly inhibited by D-lactose. The lectin exhibited powerful resistance to alkali and kept about 30% hemagglutination activity at pH 14.0, whereas its capacity of acid resistance was weak. The maximum hemagglutination activity of LML maintained at a temperature range from 20°C to 50°C. Moreover, the structure of LML was preliminarily studied, indicating it contained abundant glutamic acid, histidine, and serine, and its secondary structure containedα-helix (4.97%),β-sheet (27.55%), turns structure (49.78%), and unordered structure (17.70%).

A novel thyroglobulin-binding lectin from the brown alga Hizikia fusiformis and its antioxidant activities

A lectin (HFL) was isolated from the brown alga, Hizikia fusiformis, through ion exchange on cellulose DE52 and HPLC with a TSK-gel G4000PWXL column. SDS-PAGE showed that HFL had a molecular mass of 16.1 kDa. The HPLC (with a TSK-gel G4000PWXL column) indicated that HFL is a tetramer in its native state. The total carbohydrate content was 41%. Glucose, galactose and fucose were the monosaccharide units of HFL, and the normalized mol% values were 6, 14 and 80, respectively. HFL contains a large amount of the acidic amino acid, Asx. The β-elimination reaction suggested that the oligosaccharide and peptide moieties of HFL may belong to the N-glucosidic linkage. The amino acid sequences, of about five segments of HFL, were acquired by MALDI-TOF/TOF, and the sequences have no homology with other lectins. HFL was found to agglutinate sheep erythrocytes. The hemagglutination activity was inhibited by thyroglobulin, from bovine thyroid, but not by any of the monosaccharides tested. The lectin reaction was independent of the presence of the divalent cation Ca(2+). HFL showed free radical scavenging activity against hydroxyl, DPPH and ABTS(+) radicals.