A new high molecular weight agglutinin from garlic (Allium sativum)

Erythrocyte agglutination by lectins from Allium sativum was inhibited only by mannose of the sugars tested. However, asialofetuin was more effective inhibitor of agglutination as compared to mannose. This led to the use of an asialofetuin-silica affinity column to isolate agglutinins of 110 and 25 kDa (ASA(110) and ASA(25)). While ASA(25) is a dimeric protein comprising of subunits of 12.5 and 13.0 kDa, ASA(110) is a glycoprotein of two identical subunits of 47 kDa. ASA(110) revealed to have a high content of aspartic acid, glycine, leucine and serine but low content of cysteine and methionine. It contains 14 residues of neutral sugars in addition to 43 residues of hexosamines per mole of lectin and requires metal ions for its functional conformation. Serological cross-reactions with other species showed some common epitopes of ASA(110) and ASA(25) present in A. porrum, A. ascalonicum, Narcissus alba, PHA and Con A but not in A. cepa. ASA(110) with CHO cells indicated it to be weakly cytotoxic with LD(50) of 160 mu g/ml.