Occurrence of a Soluble and Low Molecular Weight Xyloglucan and Its Origin in Etiolated Mung Bean Hypocotyls

A soluble xyloglucan was isolated from the buffer-soluble fraction of homogenates of etiolated mung bean hypocotyls. The general properties and structure of the soluble xyloglucan were similar to those of xyloglucan from the cell walls of etiolated mung bean hypocotyls. The molecular weight of the soluble xyloglucan was about 20,000, whereas that of the wall xyloglucan was about 160,000.The origin of the soluble xyloglucan in the hypocotyl was investigated with special reference to the role of xyloglucan as reported by some authors. The results indicated that the ratio of the wall xyloglucan and soluble xyloglucan contents to total cell wall polysaccharides was different between elongated and non-elongated regions of etiolated mung bean hypocotyls. The enzyme responsible for the hydrolysis of xyloglucan is xyloglucanase and it was found in etiolated mung bean hypocotyls.