Title: Laminaran
CAS Registry Number: 9008-22-4
Additional Names: Laminarin
Literature References: A polysaccharide found in brown seaweed and occurring principally in the Laminaria spp. Linear polymer composed of b-(1®3)-linked glucose residues; may contain small amounts of b-(1®6) linkages as interresidue linkages or as branch points and 2-3% D-mannitol as end groups. Two forms of laminaran are recognized; they are referred to as soluble and insoluble laminaran: Percival, Ross, J. Chem. Soc. 1951, 720. Structure: Peat et al., ibid. 1958, 724, 729; 1960, 175; Goldstein et al., Chem. Ind. (London) 1959, 124; Annan et al., ibid. 1962, 984; Annan et al., J. Chem. Soc. 1965, 885; Maeda, Nisizawa, Carbohydr. Res. 7, 97 (1968). Structure of soluble laminaran from Eisenia bicyclis: T. Usui et al., Agric. Biol. Chem. 43, 603 (1979). NMR studies of laminaran: D. Gagnaire, Org. Magn. Reson. 11, 344 (1978); H. Friebolin et al., ibid. 12, 216 (1979). Review: W. A. P. Black, E. T. Dewar in Industrial Gums, R. L. Whistler, Ed. (Academic Press, New York, 2nd ed., 1973) pp 137-145.
Derivative Type: Water-insoluble laminaran
Properties: Isolated from L. cloustoni Edmondst., Laminariaceae, is pptd spontaneously from the aq acid extract of the plant. Has lower degree of branching than the sol form. Typical analysis of the dry material: 92.5% polyglucose, 0.4% non-volatile matter; [a]D16 -13.4° (c = 0.9). Amorphous triacetate, (C12H16O8)n, [a]D16 -63.5° (c = 0.4 in chloroform).
Optical Rotation: [a]D16 -13.4° (c = 0.9); [a]D16 -63.5° (c = 0.4 in chloroform)
Derivative Type: Soluble form
Properties: Isolated from L. digitata, is separated from the acidified extract only after addition of a precipitant such as ethanol. Typical analysis (on dry basis): 91.2% polyglucose, 1.0% non-volatile matter; [a]D18 -11.9° (c = 2.1).
Optical Rotation: [a]D18 -11.9° (c = 2.1)
Derivative Type: Sulfate
Additional Names: Laminaran hydrogen sulfate
Properties: Laminaran can be sulfated to varying degrees. Highly sulfated products have anticoagulant properties comparable to heparin, while laminarans with few sulfate groups are antilipemic only: Besterman, Evans, Br. Med. J. I, 310 (1957).
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