Of peanut lectin

To further exploit the potential usefiilness of this new family of clusters, monoadduct 54 was saponified into 55 (0.05 M NaOH, quant) and condensed to L-lysine methyl ester using 2-ethoxy-l-ethoxycarbonyl-l,2-dihydroquinoline (EEDQ) to give extended dimer 56 in 50 % yield together with monoadduct in 15 % yield [75]. Additionally, tert-butyl thioethers 52 could be transformed into thiols by a two step process involving 2-nitrobenzenesulfenyl chloride (2-N02-PhSCl, HOAc, r.t, 3h, 84%) followed by disulfide reduction with 2-mercaptoethanol (60%). Curiously, attempts to directly obtain these thiolated telomers by reaction with thioacetic acid f ed. These telomers were slightly better ligands then lactose in inhibition of binding of peanut lectin to a polymeric lactoside [76]. 

A major disagreement exists with respect to the biological activity of peanut lectin.616,619 Terao and coworkers616 could not demonstrate mitogenicity of peanut lectin towards either normal, or neuraminidase-... 

Copolymerization of allyl a-D-galactopyranoside and acrylamide produced an insoluble pseudoglycoprotein that was used in the purification of peanut lectin. ... 

Fischer, J., Klein P.-J., Farrar, G. H., Hanisch, F.-G. and Uhlenbruck, G. 1984. Isolation and chemical and immunological characterization of the peanut-lectin-binding glycoprotein from human milk-fat-globule membranes. Biochem. J. 224, 581-589. 

The conformation of C-lactose (25a, R = H) bound to peanut lectin agglutinin has been studied through X-ray analysis.11 The bound conformation, defined by o —63, I c 120°, is practically identical to that of the parent O-lactose (25b, R = H) bound to the same protein. ( o —69, I c 118°). The authors were tempted to conclude from this particular observation that the conformational similarity in protein-bound states is a general phenomenon. Nevertheless, it is clear that the architecture of the binding site should also be analyzed (see later). In contrast, Espinosa et al.12 and Asensio et al.90 demonstrated that the three staggered conformations of C-lactose (syn-exo-<(>, syn- it syn-exo-d>, anti- H and anti-exo-, syn-ty) are recognized by three different proteins, and in some cases their behavior differs from that with natural lactose. 

One approach to this problem would be to isolate the intact lectin-receptor molecules from the cell membranes and characterize them. Work in this direction has been initiated in our laboratory, and a method for the isolation of the peanut agglutinin receptor from membranes of neuraminidase-treated human erythrocytes on a column of peanut agglutinin-polyacryl-hydrazido-Sepharose has been developed (21). The amino acid composition, D-glucosamine ancHg-galac-tosamine content, and the electrophoretic mobility on polyacrylamide gel electrophoresis in sodium... 

Another important assumption from the lectin binding studies was that hemopoietic stem cells in the mouse may carry receptors for both peanut agglutinin and soybean agglutinin. Evidence in support of this assumption was obtained when, with the aid of peanut agglutinin and soybean agglutinin a cell fraction was isolated from mouse bone marrow and spleen, which was enriched with hemopoietic stem cells and depleted of "graft-versus-host" activity. Furthermore, such a cell fraction could be used for successful reconstruction of irradiated allogeneic mice (3SH. ... 

Polymer adsorption has also been adapted to QCM sensing whereby biofunctional thin films are adsorbed on the crystal surface with non-specific binding controlled by tuning of polymer composition. This approach proved successful as applied to carbohydrate-protein interaction by Matsuura et al. through adsorption of lactose bearing amphiphilic polymers on hydrophobic surfaces which then showed RCA12o and peanut lectin (PNA) affinity [33]. Carbohydrate surfaces prepared by photo insertion into an adsorbed polymer were tested by QCM and showed the predicted affinities [34] while in another example a covalently bound glycopolymer demonstrated Concanavalin A detection ability [35]. 

Figure 11.28. Binding Selectivities of Plant Lectins. The plant lectins wheat germ agglutinin, peanut lectin, and phytohemagglutinin recognize different oligosaccharides.

Specificity as listed for each column HiTrap Lectin Test Kit 17-5109-01 4 x 1 ml columns of HiTrap Con A HiTrap Lentil Lectin HiTrap Peanut Lectin HiTrap Wheat Germ Lectin as listed above... 

A listing of the X-ray crystal structure (arranged in chronological order) of plant lectins is presented in Table 2 commencing with the structure of concanavalin A at 3 A resolution [38,39]. Interestingly, it was not until 1989 that a definitive high resolution X-ray crystal structure of the concanavalin A-methyl a-D-mannopyranoside complex was elucidated [40], and the most recently reported is that of peanut agglutinin [41]. Reviews on carbohydrate-protein interactions are also worthy of note [42-45]. 

The peanut Arachis hypogaea) contains a lectin with anti-T (Gal(Pl-3)GalNAc) activity [174]. This antigen appears on human erythrocytes following treatment with sialidase and leads to the phenomenon known as polyagglutinability as monitored by the peanut lectin [175]. Peanut agglutinin, purified by numerous affinity purification schemes, is a tetrameric protein composed of four carbohydrate-free subunits, A/f = 27000Da[176]. The lectin is a metalloprotein rich in acidic and hydroxylic amino acids and devoid of cysteine [176]. 

In normal cells, core 1 is further processed by the addition of sialic acid and blood group determinants, or by extension or branching reactions (Figure 2). The T antigen is often abnormally expressed on cancer cells and on intestinal cells from patients with inflammatory bowel disease, and binds Peanut lectin, which has been shown to stimulate cell proliferation. " The overexpression of T antigen may be due to the lack of enzymes that further process the T antigen. 

Binding and elution from Con A columns is most effective at room temperature. With WGA, the temperature does not play a role. Binding of glycoproteins to soy bean lectin or peanut lectin is optimal at 4° C. 

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