Purification and partial characterization of a lectin from Caesalpinia tinctoria Domb, ex Dc fruits

a lectin was isolated from the pod saline extract of caesalpinia tinctoria by dialoconcentration on centripep-10 and affinity chromatography on chitin column. the purified lectin was partially characterized with respect to its biochemical and structural properties. it contains 8.3 % of carbohydrate and exhibited an agglutinating activity against human erythrocytes (abo groups). its amino acid composition was characterized by a great number of acidic and hydrophobic residues and the estimated molecular mass was 12.5 kda. the presence of only one n-terminal amino acid sequence (d1-v-p-a-y-v-y-v-h-f10-g-f-g-e-e-h-r -d-v-f20-d), showed the homogeneity of the purified lectin. the far-ultraviolet circular dichroism (cd) spectrum of lectin indicated that it contains 10 % a-helix, 38 % b-sheet, 28 % unordered form and 6 % of pii (poly-l-proline ii helix conformation).