Sycamore, polysaccharide from

G.O. Aspinall, J.A. Molloy, J.W.T.Craig. Extracellular polysaccharides from suspension-cultured sycamore cells. Can J Biochem, 1%9, 47, 1063-1070... 

Isolated from a mixture of. methylated polysaccharides from sycamore (Acer pseudoplatanus) cell walls (45). Isolated from the bark of white willow (Salix alba L.) (70). 

In the reported structures of products of cellulase digestion of xyloglucans from different sources, there has been considerable variation that may reflect different action-patterns of enzyme preparations as much as actual differences in the structures of the polysaccharides. On reaction of xyloglucan from the walls and culture medium of suspension-cultured, sycamore cells,26,27 four major oligosaccharide products were isolated. Stuctures were proposed for the heptamer (Z) and the nonamer (3). 

Polysaccharides of the xyloglucan may be of relatively widespread occurrence, and examples have been reported from the bark of Engel-mann spruce (Picea engelmann), 5 red-spruce compression-wood,155 the seeds of white mustard (Brassica alba),156 and sycamore callus-cells.157 The mustard156 and sycamore157 polysaccharides are charac-... 

Pectin-like material is secreted from suspension tissue culture cells of sycamore and the rate of secretion of these polysaccharides can be measured using radioactive arabinose which is incorporated into arabinogalactans. The addition of Ca increased the steady state rate of secretion within seconds. The stimulation was brought about by an action on the normal mechanism of cell-wall polysaccharide export from the cytoplasm. It seemed therefore that the fusion of the vesicles with the plasmamembrane was a rate-limiting step and is probably a control point. The action of the Ca " " was to increase the rate of fusion at the cell membrane so that there was an immediate increase in the amount of polysaccharide secreted (35). 

Constit. of Rhamnogalacturonan II, R-10, a primary cell wall pectic polysaccharide isol. from cultured cells of Acer pseudo-platanus (Sycamore). First branched chain acidic sugar to be found as a natural product. 

Polysaccharide consisting of ( - 4)- -d-(3alpA-(l - 2)-a-L-Rhap-(l - ) backbone with arabinan and oligogalactosyl side-groups attached at 0-4 of the Rha residues. Interspecies variation is prob. due to side-chain variation. Isol. from xylem-differentiating zones of Crypto-meria japonica and from sycamore Acer pseudoplatanus). Major pectic polysaccharide component of cell walls of dicots and nongraminaceous monocots. 

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