An N-acetylglucosamine oligomer binding agglutinin (lectin) from ripe Cyphomandra betaceu Sendt. fruits

A new agglutinin (lectin), called CBL3, was purified from the juice of ripe Cyphomandra betacea Sendt. fruits until electrophoretically pure to homoge neity. The lectin is a homodimer of M-r = 50 800 with subunits of 26 200 bo und by disulfide linkages with a pi of 4.9. The agglutinating capacity of t he lectin is only inhibited by oligomers of N-acetylglucosamine in the foll owing order of potency: tetrasaccharide > trisaccharide > disaccharide. CBL 3 is not inhibited by N-acetylglucosamine, the same as all known lectins of the Solanaceae family. The human blood group recognition is non-specific. The lectin is a glycoprotein with 13.6% (w/w) of carbohydrates. The aggluti nating activity is not affected by EDTA nor by cations. Mitogenic activity was not detected. Heat and pH stability, amino acid composition, N-terminal amino acid sequence and immunological properties show substantial differen ces to the reported lectins isolated from the Solanaceae family. (C) 2001 E lsevier Science Ireland Ltd. All rights reserved.