Studies on a hemagglutinin from Bauhinia purpurea alba seeds

Abstract

A phytohemagglutinin has been purified from the seeds of Bauhinia purpurea alba. The homogeneity of the purified hemagglutinin was ascertained by ultracentrifugal analysis and electrophoresis on polyacrylamide gel. The purified hemagglutinin had a s 020 w value of 7.5 S and its molecular weight of 195,000 was estimated by sedimentation equilibrium experiments. This hemagglutinin was found to contain 11.1% carbohydrate of which mannose (4.9%) and glucosamine (3.4%) were the predominant sugars, with smaller amounts of xylose, glucose, fucose and galactose. The purified hemagglutinin agglutinated erythrocytes regardless of their ABO and MN blood group types. In hapten inhibition assays with simple sugars, the so-called Mäkela's group 2 sugars, particularly N-acetyl- d-galactosamine, were the most potent inhibitors for this purified hemagglutinin. From the titration assays with enzyme-treated erythrocytes and from the hemagglutination-inhibition assays using partially hydrolyzed trypsin fragments from erythrocytes as inhibitors, it was assumed that the receptor sites for this hemagglutinin were at least partly covered by sialic acid and mainly composed of alkali-labile carbohydrate chains on the cell surface.