A Carbohydrate-Binding Arabinogalactan-Protein From Liquid Suspension Cultures of Endosperm From Lolium multiflorum Academic Article uri icon

abstract

  • Water-soluble arabinogalactan-proteins have been isolated from tissue-cultured rye grass endosperm cells and their culture medium by precipitation with the β-glucosyl Yariv artificial antigen. The intracellular and extracellular polymers are similar in composition and molecular size (apparent mol. wt 2.2 — 2.8 × 105). The protein portion represents up to 7% of the molecule and is rich in hydroxyproline, alanine and serine. The carbohydrate portion (84%) consists solely of arabinose (36%) and galactose (64%) and methylation analysis shows it to be a branched 1,3 : 1,6-galactan substituted by arabinofuranosyl residues. The carbohydrate compositions and methylation analyses for polymers precipitated by the β-glucosyl Yariv antigen from lima beans, cashew, tomato, silver beet and asparagus and an arabinogalactan-peptide from wheat endosperm are compared. As a group, they show homologies both in their peptide and polysaccharide portions. A histochemical method, based on precipitation with the β-glucosyl Yariv antigen, showed the binding polymers to be localized in discrete irregular vesicles in the tissue-cultured rye grass endosperm cells. Native rye grass endosperm cells show staining between starch granules, and staining is also seen in the aleurone cells of barley, wheat and rye grass.

publication date

  • 1977