Abstract
1. Methods were developed for the extraction, fractionation and purification of the more soluble polysaccharides of mustard-seed embryos. 2. One of these components was a pure homopolysaccharide, an araban, which was characterized by analysis, optical rotation, chromatography on diethylaminoethylcellulose and electrophoresis; the hydrolysis products of the methylated polysaccharide were isolated and characterized by the formation of crystalline derivatives. From these studies it emerges that mustard-seed araban is very similar to the family of pectic arabans, except that it is more highly branched than usual and contains a proportion of 1-->2-linkages. 3. A survey of the other polysaccharides of mustard seed, both in the embryos and in the seed coats, suggests a predominance of pectic-type polysaccharides.