Further characterization of glucose-specific peanut root lectin (PRA II).

Amino acid analysis of PRA II, a glucose-specific lectin isolated from 7 day-old peanut seedling roots shows that this lectin is rich in glycyl (103 per mole) and seryl residues (59 per mole), and poor in essential amino acids, the acidic amino acid content is higher than the basic amino acids and that its amino acid composition differs from its seed counterpart (PNA), although neither of the lectins contains cystein. PRA II has two carbohydrate binding sites per molecule as determined by equilibrium dialysis. Modifications of the specific amino acid residues of the lectin with group specific reagents indicate that hydroxyl group of tyrosine is involved in the binding of carbohydrate to PRA II.

Studies on hemagglutinins (lectins) from plasma of murrel fish, family Channidae.

Hemagglutinating activity can be identified in the plasma of different species of murrel fish. This activity may be divided into four types according to their agglutinability towards erythrocytes from different sources. Type I plasma agglutinates human blood group A erythrocytes, type II can agglutinate neuraminidase treated human A B O erythrocytes, type III shows no agglutinating activity towards human erythrocytes, while type IV agglutinates human erythrocytes non-specifically. All of them bind to DEAE-cellulose but elute out by different salt concentrations. Type IV plasma is found to be a combination of three separate hemagglutinins, which are separable by sequential binding to human A B O erythrocytes. Blood group A specific lectin activity is purified from this plasma using formalinised A group erythrocytes. The apparent homogeneity of this purified lectin is established by polyacrylamide gel electrophoresis, isoelectric focusing and immunodiffusion. This agglutinin is antigenically identical with that isolated from type I plasma by affinity chromatography on N-acetyl-D-galactosamine coupled to epoxy-activated cellulose column. Their molecular weights are also found to be identical (Mr 140,000) in polyacrylamide gel electrophoresis, having two identical subunits. Forssman glycolipid (0.03 mM) was found to be the most potent inhibitor of agglutination, although Gal beta 1-3 GalNAc (0.09 mM) is also a good inhibitor. Exhaustive dialysis of the purified lectin (hemagglutinin) against EDTA denatures it irreversibly by dissociating it to its subunit structure. Thus human A group agglutinating activity isolated from type I and type IV plasma are identical.