Plants apiose-containing polysaccharides

Incubation of D-[U-I4C]apiose with sterile Lemma minor (duckweed) produced less than 0.01% incorporation into the cell-wall polysaccharides.75 Most of the d-[U-i4C]apiose appeared as 14C02 some remained in solution in the medium and in the duckweed plants, primarily as degradation products of D-[U-14C]apiose, but not as the branched-chain sugar.75 There is an efficient synthesis of the [U-14C]apiose moiety of cell-wall polysaccharides from D-[U-14C]glucose under similar conditions.81 Of the plant tissues tested, only L. minor contained an enzyme system able to metabolize free apiose. Carrot, lettuce, and spinach tissues are unable to metabolize the free, branched-chain sugar.75... 

In comparison with mammals, plants contain considerably more GTs because, in addition to the reactions carried out by mammalian GTs, they are required to convert the products of photosynthesis into diverse cell carbohydrates. For example, these GTs synthesize cell wall polysaccharides as well as secondary metabolites and xenobiotics. Plant GTs differ from mammalian GTs even more by their diversity of nucleotide donors. They use not only eight of the nine mammalian nucleotide donors, but numerous others such as UDP-L-rhamnose, GDP-L-glucose, GDP-L-galactose, UDP-L-arabinose, UDP-D-galacturonic acid, UDP-D-apiose, and so on. (29). 

Small complex polysaccharide containing apiose, 2-0-methyl-L-fucose, 2-0-methyl-D-xylose, acetic acid, Penta-Ac, 3-deoxy-D-/yxo-heptulosaric acid and other sugars depending on source. Obt. by the action of liquefying enzymes on apple, tomato and carrot juice pectin. The main nondegraded soluble polysaccharide component of the juice. Also present in various other plant products, e.g. leaves of Panax ginseng (ginseng). 

A hitherto unobserved component of the primary cell walls of dicotyledonous plants, rhamnogalacturonan II, has been isolated and partially characterized. It is a very complex polysaccharide containing residues of ten different monosaccharides including o-apiose, 2-O-methyl-D-xylose, and 2-O-methyl-L-fucose. The polysaccharide, which accounts for 3—4% of the primary cell walls of suspension-cultured sycamore cells, is also characterized by the presence of 2-linked D-glucosyluronic acid, 3,4-linked L-fucosyl, and 3-linked L-rhamnosyl residues. These linkages have not previously been detected in polysaccharides of sycamore primary cell walls. Evidence was also presented that similar polysaccharides are present in the primary cell walls of pea, pinto bean, and tomato. 

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