Defining the carbohydrate specificities of Abrus precatorius agglutinin as T (Galβ1→3GalNAc) > I/II (Galβ1→3/4GlcNAc)

Albert M. Wu*, Shing Ru Lin, Lee Kian Chin, Lu Ping Chow, Jung Yaw Lin

*Corresponding author for this work

Research output: Contribution to journalJournal Article peer-review

67 Scopus citations

Abstract

The combining site of the nontoxic carbohydrate binding protein (Abrus precatorius agglutinin, APA) purified from the needs of Abrus precatorius (Jequirity bean), was studied by quantitative precipitin and precipitin-inhibition assays. Of 26 glycoproteins and polysaccharides tested, all, except sialic acid-containing glycoproteins and desialized ovine salivary glycoproteins, reacted strongly with the lectin, and precipitated over 70% of the lectin added, indicating that APA has a broad range of affinity and recognizes (internal) Galβ1-» sequences of carbohydrate chains. The strong reaction with desialized porcine and rat salivary glycoproteins as well as pneumococcus type XIV polysaccharide suggests that APA has affinity for one or more of the following carbohydrate sequences: Thomsen-Friedenreich (T, Galβ1→3GalNAc), blood group precursor type I and/or type II (Galβ1→3/4GlcNAc) disaccharide determinants of complex carbohydrates. Among the oligosaccharides tested, the T structure was the best inhibitor; it was 2.4 and 3.2 times more active than type II and type I sequences, respectively. The blood group I Ma-active trisaccharide, Galβ1→ 4GlcNAcβ1→6Gal, was about as active as the corresponding disaccharide (II). From the above results, we conclude that the size of the combining site of the A. precatorius agglutinin is probably as large as a disaccharide and most strongly complementary to the Galβ1→3GalNAc (T determinant) sequence. The carbohydrate specificities of this lectin will be further investigated once the related oligosaccharide structures become available.

Original languageEnglish
Pages (from-to)19130-19139
Number of pages10
JournalJournal of Biological Chemistry
Volume267
Issue number27
StatePublished - 25 09 1992

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