Laminarins

If branching is (1 —> 3), no glycol grouping will be present in any central unit and it may be seen that reaction will only occur on the terminal units. Such is the case with the polysaccharide laminarin, with the glucan of yeast membrane, and with a galactose-containing polysaccharide isolated from agar.146-148... 

The reaction of these aldehydes, derived from periodate oxidation, with carbonyl reagents has also been investigated. Studies 147 148 were made on oxidized laminarin, a (1 —> 3)-linked polysaccharide, in which only the terminal residues had been oxidized. The addition of phenylhydrazine acetate detached the remainder of the terminal residue as glyoxal phenyl-osazone. When the aldehydic compounds derived from the periodate oxidation of raffinose and trehalose818a were reacted with p-nitrophenylhydrazine, the authors were surprised to find that one molecule of oxidized raffinose, containing six aldehydic functions, reacts with only three molecules of the reagent, and that the four aldehydic functions of the oxidized trehalose molecule react with only two. The reactions of periodate-oxidized carbo-... 

The same group investigated the separation of fluorescently labled sugars by different CDs as well as linear polysaccharides (dextrin 10, dextran, laminarin, and alginic acid) and oligosaccharides in the presence of borate... 

Laminaria angusta Kjellim. L. cichorioides Miyabe. L. japonica Aresch. L. longipedalis Okam. L. religiosa Miyabe. Kun Bu or Hai Dai (thallus) Iodine, potasium, calcium, amino acids, laminarin, laminine, algin.33 Improve thyroid function, correct the malignant vicious cycle effect of iodine deficiency, lower blood pressure. 

Laminarin is the reserve carbohydrate of the sublitoral brown algae, especially Laminaria. There are two types of laminarin as regards solubility, the normal or water-insoluble laminarin (from L. cloustoni) and a soluble type (from L. digitata). These two kinds of laminarin differ only in solubility and are otherwise indistinguishable in composition and structure. They will not be further differentiated in this description. 

From these results it is apparent that laminarin is composed entirely of glucose, the combined sulfate and fucose detected being due to admixture with fucoidin. 

On acetylation of laminarin followed by simultaneous deacetylation and methylation, Barry112 obtained methylated laminarin, among the hydrolytic products of which he identified 2,4,6-trimethyl-D-glucose... 

Barry114 isolated a disaccharide, laminaribiose, on the partial hydrolysis of laminarin by enzymes (digestive juice of the snail Helix pomatia or H. aspersa) or by acid (seven hours with N oxalic acid on the water-bath). He showed that this disaccharide consisted solely of D-glucose and considered it to be 3-j3-D-glucopyranosyl-D-glucopyranose (XXIX). 

FIGURE 1 Potential hydrolysis rates of six structurally distinct polysaccharides in seawater (A) and surface sediments (B) from Skagerrak and Svalbard. Pull = pullulan, lam = laminarin, xyl = xylan, fu = fucoidan, ara = arabinogalactan, chon = chondroitin sulfate. Note the differences in scale on the y axes for sediments and for seawater. [Skagerrak data from Arnosti (2000).]... 

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