An arabinogalactan-protein from cell culture of Malva sylvestris

An arabinogalactan-protein (AGP) from suspension culture medium of Malva sylvestris was isolated by precipitation with beta-glucosyl Yariv reagent, followed by gel-permeation chromatography. It revealed characteristic features of AGPs: a high amount of polysaccharide with a ratio of galactose to arabinose of 1.9: 1, some uronic acids, and a small protein moiety with the main amino acids serine, alanine and hydroxyproline. The molecular weight was estimated to be 1.3 x 10(6) Da. Linkage analyses showed that the AGP is composed of a highly branched core polysaccharide of 3-, 6-, and 3,6-linked Galp residues with terminal Araf, GlcAp and Galp. Partial acid hydrolysis resulted in loss of Araf residues at the periphery of the molecule and heavily reduced its reactivity with beta-glucosyl Yariv antigen.