Rhodymenia palmata, xylans

Unlike the xylans already discussed, Rhodymenia palmata /3-D-xylan contains mixed (l- 3) and (l- 4) linkages. On reaction with a cellulase that had /S-D-xylanase activity,74 a series of (l- 4) and mixed-linkage xylosaccharides was produced that included (1 - 4)-0-xylo-biose, -triose, -tetraose, and a mixed-linkage trisaccharide, namely, 32-0-/3-D-xylosyl-xylobiose (17). endo-(l - 4)-/3-D-Xylanase has been shown62 to catalyze... 

H. Bjomdal, K. E. Eriksson, P. J. Garegg, B. Lindberg, and B. Swan, Studies on the xylan from the red seaweed Rhodymenia palmata, Acta Chem. Scand., 19 (1965) 2309-2315. 

The marine algal D-xylan obtained from Rhodymenia palmata has been shown250-251 to be composed of /3-d-(1 — 3)- and /3-D-(l — 4)-linked D-xylose residues in a single D-xylan chain, and it is suscep-... 

Structures of Xylo-oligosaccharides Isolated from Enzymic Hydrolyzates of Rhodymenia palmata D-Xylan... 

This starch differs in that no amylose is present, but it resembles amylopectins in many of its properties. There is little evidence for starch in oAer red algae [e.g., Rhodymenia palmata (dulse)]. In this alga, the major polysaccharide is a water-soluble xylan made up of random 1,3-and 1,4-linked units. Other 1,3-, 1,4-, and mixed 1,3- and 1,4-xylans have been isolated from a number of red algae (Percival, 1970, 1979). 

A xylan from esparto grass 63, 64) is a singly branched chain of about 76 D-xylopyranose units linked jS-D-1— 4 in the main chain but with a 1—>3 link at the point of branching. From the cell wall of pear wood, another similarly single-branched xylan is obtained which has about 115 D-xylo-pyranose units, but it contains, in addition, a terminal D-glucopyranosyl-uronic acid unit at one point 65), The xylan from the red seaweed 57,58) Rhodymenia palmata seems to be composed only of D-xylopyranose units... 

True xylans have been found in algae. The xylan from the red seaweed Rhodymenia palmata contains 80% of u-(i -> 4) links and 20% of fi-v-(i - 3) links, while the green seaweed Caulerpa filiformis contains a xylan with only p-v-(i -> 3) links. 

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