Biosynthesis of Oligosaccharides and Polysaccharides in Plants

The Site of Cellulose Synthesis

“…Surface enzyme must be extremely labile, however, because standard homogenization procedures result in almost complete destruction of its activity (21). Thus, cell-free systems contain membrane-bound cellulose synthetase activities which together account for a very small fraction of either cellsurface activity (21) or the normal rates of cellulose deposition observed in vivo (1,2,9,21). In homogenates derived from elongating or swelling tissues, synthetase activity is found apparently associated with Golgi membrane or ER3 vesicles (e.g., in peas; see refs.…”

Frost and Chilling Injury to Growing Plants

“…It is possible that permeable membranes allow particular polysaccharides to move onto the extracellular surfaces where they can interact with growing ice crystals. Hassid (1969), in his review of polysaccharide biosynthesis in plants, emphasizes the further importance of the plasma membrane as a source of cell wall building materials.…”

Sequencing and analysis of the divergon comprising gtaB, the structural gene of UDP-glucose pyrophosphorylase of Bacillus subtilis 168

“…UDPG participates in a variety of enzymic reactions which include: (i) metabolism of polysaccharides (glycogen, starch, laminarin and cellu-lose), disaccharides (sucrose, trehalose), b-glucosides, UDP-glucuronate and glucosyl-ceramide (Hassid, 1969 ;White et al, 1973); (ii) galactose entry into glycolysis; (iii) synthesis of periplasmic membrane-derived oligosaccharides (Miller et al, 1986) which could play a role in osmotic adaptation of Gram-negative bacteria (Schulman & Kennedy, 1977) ; (iv) glucosylation of hydroxymethylcytosine residues in cells infected by Teven bacteriophages (Shedlovsky & Brenner, 1963) ; and (v) synthesis of the core region of lipopolysaccharides in Gram-negative bacteria (Sundararajan et al, 1962). In the Gram-positive bacterium Bacillus subtilis, strain 168, UDPG is required for the glucosylation of the poly(g1y-cerol phosphate) [poly(groP)] (Young, 1967), the major cell wall teichoic acid (Baddiley, 1970), and for the polymerization of the secondary anionic polymer, the poly( 3-O-~-~-glucopyranosyl-N-acetylgalactosamine 1 -phosphate [poly(Glc-GalNAc 1 -P)] (Shibaev et al, 1973).…”