A comparison of the two lectins from Vicia cracca.
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Amino Acid Sequence↗
Biomedical subjects
H Rüdiger
Publications and source records attributed to H Rüdiger.
Lectin-associated proteins from the seeds of Leguminosae.
The seeds of Pisum sativum (pea), Canavalia ensiformis, Vicia faba, Vicia sativa, and Ricinus communis were shown to contain proteins which are associated to the respective lectins (lectin binders). The lectin binders from Pisum sativum and Canavalia ensiformis were studied more closely. Both are single proteins not resembling the variety of membrane glycoproteins found in animals and plants which bind to lectins. The pea lectin binder is a tetrameric glycoprotein composed of identical subunits of the Mr 51 000. Its interaction with the lectin is abolished by acidic buffers or by glucose. The Concanavalin A binder, which does not contain sugar, is composed of one kind of subunit, Mr of 35 000. As in the case of the pea lectin binder, glucose and acid dissociate the lectin-lectin binder complex, but in contrast to the pea lectin binder low NaCl concentrations also cause this effect. During germination and growth, the Concanavalin A binder appears in the roots.
Concanavalin A↗
Purification and characterization of a mitogenic lectin and a lectin-binding protein from Vicia sativa.
From the seeds of Vicia sativa, a novel mitogenic lectin was isolated. Purification was carried out by affinity chromatography on Sephadex G-100. The tetrameric lectin is a glycoprotein with a molecular weight of Mr 40 000; it consists of two large beta-subunits (Mr 14 000) and two small alpha-subunits (Mr 6000). The N-terminal sequence of both subunits and their amino acid compositions were determined. The lectin agglutinates human erythrocytes, preferring group B, and erythrocytes from rabbits and horses; no agglutination takes place with sheep erythrocytes. Agglutination is inhibited by mono-, di- and tri-saccharides with the configuration of glucose at the free 4-hydroxyl group. The lectin stimulates mitosis in lymphocytes of mice. From the seeds of the same plant, a protein was isolated which binds to the lectin described above. The lectin binder consists of subunits with a molecular weight of 53 500.
Amino Acid Sequence↗
[Lectins, sugar-binding plant proteins].
Lectins are proteins which can bind to the surfaces of animal and human cells. They are widespread in the plant and animal kingdom. Though many lectins have been isolated and characterized, and though some are extensively used as cell surface "tools", their biological role is only subject to hypotheses.
Animals↗
Purification and properties of blood-group-specific lectins from Vicia cracca.
The lectins from the seeds of Vicia cracca react specifically with human blood group A erythrocytes. They were purified by affinity chromatography on an adsorbent containing matrix-bound N-acyl-D-galactosamine. By a continuous pH gradient the lectins could be separated into two fractions each of which was shown to consist of several agglutinating species. The behaviour of both fractions in affinity chromatography was paralleled by the pH dependence of the interaction with the hapten sugar N-acetyl-D-galactosamine. Both lectin fractions have the same molecular (125000) and subunit (33000) weights, display the same pH dependence of their titre against A1 erythrocytes, and bind to N-acetyl-D-galactosamine at pH 8 with the same constant of about 6 X 10(3)M-1.
ABO Blood-Group System↗
[Purification and properties of the tetrahydropteroylglutamate methyltransferase from green beans (Phaseolus vulgaris) (author's transl)].
The tetrahydropteroylglutamate methyltransferase from green beans (Phaseolus vulgaris) has been purified 80-fold by ion exchange chromatography and gel filtration. Optimal methyl transfer is found at pH 6.5 and 39 degrees C. Even at 0 degrees C, however, a considerable catalytic rate is observed. The Michaelis-Menten constants for homocysteine and 5-methyltetrahydropteroylglutamate are 0.43mM and 2.4 mM, respectively. Magnesium ions enhance the activity. Even purified preparations appear to contain traces of magnesium ions firmly bound, since a residual activity is found without addition of magnesium salts. Though the reaction requires anaerobiosis, an excess of reducing agents is inhibitory. The molecular weight of the transferase, determined by gel filtration, is 40 000 +/- 6%.
5-Methyltetrahydrofolate-Homocysteine S-Methyltran↗