About the Lectin

A lectin with complex blood group and carbohydrate specificity has been isolated from the seeds of the spindle tree. Although the lectin reacts with several blood groups it does not react with A 1 blood group substance and it is not inhibited by any simple sugars. The molecular weight and subunit composition of the lectin is also somewhat ambiguous. There are four major bands between 17,000-67,000 Da when analyzed by SDS-PAGE. After treatment of the lectin with β-mercaptoethanol, the two higher molecular weight bands disappear. At the same time, the lowest molecular weight band shows an increase in staining intensity while the other low molecular weight component shows a decrease in intensity 1 . When analyzed by sedimentation equilibrium, the lectin has an apparent molecular weight of 166,000 2 , however, lower molecular weight species have been reported for other preparations of the lectin 3 . The lectin activity is not inhibited by simple sugars but it is inhibited by the blood group B oligosaccharide (Gal α(1,3) [Fuc α(1,2)] Gal β(1,3 or 1,4) GlcNAc), and to a lesser degree by the blood group H oligosaccharide (Fuc α(1,2) Gal β(1,3 or 1,4) GlcNAc). Treatment of murine macrophages with α-galactosidase decrease EEA binding somewhat, and subsequent treatment with α-L-fucosidase reduced the binding still further, 4 indicating that both Gal and Fuc residues play a role in binding. EEA is the only anti-H specific lectin which will react with H type 1 1 . The immobilized lectin has been used to purify C2 from human plasma 5 . EEA also binds laminin isolated from the mouse EHS sarcoma. It is a marker for endothelial cells in mammals 6 , and has been used attached to magnetic beads to purify endothelial cells. 7 EEA is stable when stored in liquid form at 4°C. Preparations have been reported to retain activity even after 8 years of storage.

REFERENCES

  1. Petryniak, J. and Goldstein, I. J. (1987). Meth. Enzymol. 138 : 552-561.
  2. Petryniak, J., et al. (1977). Arch. Biochem. Biophys. 178 : 118-134.
  3. Pacák, F. and Kocourek, J. (1975). Biochem. Biophys. Acta. 400 : 374-386.
  4. Petryniak, J. (1992) Glycoconj. J. 9 : 92-98
  5. Schultz, D. R. and Arnold, P. I. (1984). Acta. Path. Micro. Immun. Scand. Sect. C. Supplement. 284 : 59-66.
  6. Roussel, F., et al. (1992) Lab. Animals 26 : 114-121
  7. Gomez, D. E., et al. (1993) In Vitro Cell. Dev. Biol. Animal 29A : 451-455

Product Characteristics
Buffer 0.01M Phosphate – 0.15M NaCl, pH 7.2-7.4
Blood Group B, O(H), A2
Activity 50 μg/ml will agglutinate human A2 erythro-cytes.
Inhibitory Carbohydrate Not inhibited by simple sugars.
Molecular Weight Not clearly defined. Multiple bands appear on SDS-PAGE.
Caution Avoid freezing all forms of this lectin.