Study On Purification, Characterization And Conformation Of Alisma Plantago-quatica Lectin

The studies on Alisma plantago-aquatica lectin (APL) mainly included the purification , characterization of APL, and the relationship between structure and bioactivity of APL. APL was isolated from the bulbs of Alisma plantago-aquatica by extraction, precipitation with (NH₄)₂SO₄, ion-exchange chromatography on DEAE-Sepharose, chitin-aff inity chroma-tography column and followed by gel filtration on Sephacryl S-100. The purified lectin showed both a single protein band on SDS-PAGE under the presence or not of the β-mercaptoethanol, and the molecular weight was 22. 4KD. The molecular weight was also 22. 5KD determined further by gel filtration on Sephacryl S-100. The results implied that APL was a single protein. APL can agglutinate all human ABO system groups erythrocyte at 1.8ug/mL and can not agglutinate rabbit erythrocyte. The results of carbohydrate inhibition assay showed that N-Acetyl-D-glucosamine can inhibit the agglutinating activity of APL. Test of the neutral carbohydrate indicated the lectin APL was a glycoprotein which contained 4. 26% saccharide.The native APL exhibited a characteristic circular dichroic (CD) spectrum, double negative bands centered at 195nm and 200nm. It was estimated that APL was a high α- helix protein. The fluorescence spectrum (FLS) of APL excited at 280nm and 295nm showed a maximum peak both at...