Separation and some properties of Aloe vera L. leaf pulp lectins.
The separation and partial purification of two lectins from the leaf pulp of Aloe vera L. (=barbadensis Miller) is presented. The fraction showing haemagglutinating activity was precipitated at 50% ammonium sulphate concentration from the crude leaf pulp extract. The precipitate thus obtained, after dialysis, was applied to a hydroxylapatite column. Stepwise elution resulted in two peaks showing haemagglutinating activity eluted with 5 mM (Aloctin I) and 20 mM (Aloctin II) phosphate buffers. Haemagglutinating activity was estimated visually by adding a 4% rabbit erythrocyte suspension to serial two-fold dilutions of the lectins in microtitration plates. None of the 20 sugars tested inhibited haemag--glutinating activity of Aloctin I up a concentration of 500 mM. Aloctin II was inhibited by N-acetyl-D--galactosamine at 250 mM concentration. Of 10 metal ions tested, only Al(3+) salts were found to activate Aloctin I and II. On the other hand, it was shown that neither lectin possessed any alpha- and beta- galactosidase or alpha- and beta- glucosidase activity. The lectins were of glycoprotein structure containing approximately 5% neutral sugar. The specificity of the lectins towards human and rat erythrocytes was investigated.
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Department of Biochemistry, Faculty of Pharmacy, University of Istanbul, 34452 Universite, Istanbul, Turkey.
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D000017:ABO Blood-Group System; D000504:Aloe / Q000737:chemistry* / Q000627:therapeutic use; D000818:Animals; D004912:Erythrocytes / Q000187:drug effects; D006026:Glycoside Hydrolases / Q000032:analysis; D006386:Hemagglutination Tests; D006801:Humans; D037102:Lectins / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology*; D008517:Phytotherapy; D018515:Plant Leaves; D037121:Plant Lectins; D010946:Plants, Medicinal; D011817:Rabbits; D051381:Rats; D017208:Rats, Wistar; D012204:Rh-Hr Blood-Group System
D000017:ABO Blood-Group System; D037102:Lectins; D037121:Plant Lectins; D012204:Rh-Hr Blood-Group System; D006026:Glycoside Hydrolases