Phosphomannosyl-Residues-Enzymes-Component-Recognition-Marker-Binding-Man-Receptor-Translocation-Lysosomes-b

The high mannose-type oligosaccharide units of lysosomal enzymes are phosphorylated by the following mechanism N-acetylglucosamine 1-phosphate is transferred to the 6 position of a mannose residue to form a phosphodiester; then N- acetylglucosamine is removed to expose a phosphomonoester. We examined the kinetics of this phosphorylation pathway in the murine lymphoma BW5147 cell line to determine the state of oligosaccharide phosphorylation at the time the newly synthesized lysosomal enzymes bind to the receptor. Cells were labeled with [2-(3)H]mannose for min and then chased for various times up to 4 h. The binding of newly synthesized glycoproteins to the Man 6-P receptor was followed by eluting the bound ligand with Man 6-P. 2'-Fucose lactose -bound material was first detected at min of chase and reached a maximum at min of chase, at which time approximately percent of the total phosphorylated oligosaccharides were associated with the receptor. During longer chase times, the total quantity of cellular phosphorylated oligosaccharides decreased with a half-time of 1 h, suggesting that the lysosomal enzymes had reached their destination and had been dephosphorylated.

The structures of the phosphorylated aligosaccharides of the eluted ligand were then determined and compared with the phosphorylated oligosaccharides of molecules which were not bond to the receptor. The major phosphorylated oligosaccharide species present in the nonreceptor-bound material contained a single phosphosphodiester at all time examined. In contrast, receptor-bound oligosaccharides were greatly enriched in species possessing one and two phosphomonoesters. These results indicate that binding of newly synthesized lysosomal enzymes to the Man 6-P receptor occurs only after removal of the covering N- acetylglucosamine residues.An efficient and stereoselective synthesis of beta-D-Arap-(1--2)-beta-D-Galp-(1--3)-beta-D-Galp-(1--4)-alpha-D-Manp, a tetrasaccharide fragment of Leishmania major lipophosphoglycan.A tetrasaccharide fragment of Leishmania major lipophosphoglycan (which seems to be involved in a biological mechanism for the parasite transmission) has been synthesised using the thioglycoside, trichloroacetimidate and halide-exchange glycosylation procedures and step-wise chain elongation strategy.Fructo-oligosaccharides from Urginea maritima.

Fructo-oligosaccharides from red squill (Urginea maritima) were isolated by precipitation with methanol, GPC on Biogel P2P4, and reversed-phase HPLC. Structures of the tri- and tetra-saccharides were verified by the reductive cleavage method. A tetrasaccharide that contained both (2--1)- and were analysed by the reductive cleavage method without prior purification by reversed-phase HPLC. The mode of biosynthesis of sinistrin is discussed.Extracellular expression of agarase rAgaM1 in Bacillus subtilis and its ability for neoagaro-oligosaccharide production.State Oceanic Administration (SOA), Xiamen, China.An agarase gene (agaM1) was cloned, expressed and characterized by using Escherichia coli as host strain, revealing the outstanding properties of recombinant AgaM1 (rAgaM1) in agarose degradation and neoagaro-oligosaccharides extracellularly expressed in Bacillus subtilis, and we aim to assess the ability of the supernatant of recombinant B.

subtilis fermentation broth containing rAgaM1 to degrade agarose without protein purification, which would save the cost of purification and avoid the activity loss during purification. The pH and temperature optima for the supernatant were 7 and  °C, respectively. The supernatant containing rAgaM1 has outstanding stability against  °C and  °C. Besides, we detailedly studied the possible influence factors of rAgaM1 expression in the supernatant, including pH, temperature, isopropyl β-D-thiogalactoside (IPTG) concentration, initial optical density at a wavelength of 0 nm (OD0 ), and induction time, and the optimum conditions for rAgaM1 expression by B. subtilis were confirmed. Moreover, the supernatant was able to produce NAs by using the Gracilaria lemaneiformis, whose cells were broken by autoclaving, as substrate, and a total of 11 µmol ml-1 of NA, including neoagarotetraose and neoagarohexaose, was produced after degradation for 48 h. This ability could save the cost of substrates in NA production, although the method requires a further study.

2'-Fucose lactose reveal that the NAs with great potential in food and pharmaceutical industries could be inexpensive to make by the supernatant containing rAgaM1 of B.