7420-23-7Relevant academic research and scientific papers
Cross-utilization of b-galactosides and cellobiose in Geobacillus stearothermophilus
Shulami, Smadar,Zehavi, Arie,Belakhov, Valery,Salama, Rachel,Lansky, Shifra,Baasov, Timor,Shoham, Gil,Shoham, Yuval
, p. 10766 - 10780 (2021/01/06)
Strains of the Gram-positive, thermophilic bacterium Geobacillus stearothermophilus possess elaborate systems for the utilization of hemicellulolytic polysaccharides, including xylan, arabinan, and galactan. These systems have been studied extensively in strains T-1 and T-6, representing microbial models for the utilization of soil polysaccharides, and many of their components have been characterized both biochemically and structurally. Here, we characterized routes by which G. stearothermophilus utilizes mono- and disaccharides such as galactose, cellobiose, lactose, and galactosyl-glycerol. The G. stearothermophilus genome encodes a phosphoenolpyruvate carbohydrate phosphotransferase system (PTS) for cellobiose. We found that the cellobiose-PTS system is induced by cellobiose and characterized the corresponding GH1 6-phospho-b-glucosidase, Cel1A. The bacterium also possesses two transport systems for galactose, a galactose-PTS system and an ABC galactose transporter. The ABC galactose transport system is regulated by a three-component sensing system. We observed that both systems, the sensor and the transporter, utilize galactose-binding proteins that also bind glucose with the same affinity. We hypothesize that this allows the cell to control the flux of galactose into the cell in the presence of glucose. Unexpectedly, we discovered that G. stearothermophilus T-1 can also utilize lactose and galactosyl-glycerol via the cellobiose-PTS system together with a bifunctional 6-phospho-b-gal/glucosidase, Gan1D. Growth curves of strain T-1 growing in the presence of cellobiose, with either lactose or galactosyl-glycerol, revealed initially logarithmic growth on cellobiose and then linear growth supported by the additional sugars. We conclude that Gan1D allows the cell to utilize residual galactose-containing disaccharides, taking advantage of the promiscuity of the cellobiose-PTS system.
Synthesis of glycosyl glycerols and related glycolipids
Suhr, Rene,Scheel, Oliver,Thiem, Joachim
, p. 937 - 968 (2007/10/03)
Several isomeric glycosyl glycerols were synthesized. Acetylated allyl glycosides of D-glucose and D-galactose were transformed into 1-O-(glycopyranosyl)-rac-glycerols in a three step procedure via the corresponding 2,3-epoxypropyl glycosides and the peracetylated glycosyl glycerols. Tetra-O-benzyl-D-glucose was glycosylated with 1,3-di-O-benzylglycerol to give the α-anomer preferentially. The 2-O-(tetra-O-acetyl-β-glycopyranosyl)-sn-glycerols and 2-O-(β-glycopyranosyl)-sn-glycerols of D-glucose, D-galactose and N-acetyl-D-glucosamine and the corresponding α-derivatives of D-mannose were synthesized by selective glycosylation methods from 1,3-di-O-benzylglycerol and 1,3-O-benzylideneglycerol, respectively, and activated sugar compounds followed by hydrogenolysis. After long chain acylation and selective deacetylation the 1,3-di-O-acyl-2-O-β-glycopyranosyl)-sn-glycerols of D-glucose, D-galactose and N-acetyl-D-glucosamine and the corresponding α-derivative of D-mannose were synthesized.
New enzyme catalyzed synthesis of monoacyl galactoglycerides
Bjoerkling, Fredrik,Godtfredsen, Sven Erik
, p. 2957 - 2962 (2007/12/18)
1-Acyl-3-O-β-d-galactopyranosylglycerides have been prepared by β-galactosidase catalysedtrans-galactosidation of lactose (1) or o-nitrophenyl galactopyranoside (4) with 2,3-epoxypropanol (2) and subsequent opening of the so formed 1-O-β-d-galactopyranosyl-2,3-epoxypropanol (3) with a fatty acid.
Formation of Transfer Products from Soybean Arabinogalactan and Glycerol by Galactanase from Penicillium citrinum
Nakano, Hirofumi,Takenishi, Shigeyuki,Watanabe, Yasuto
, p. 1913 - 1922 (2007/10/02)
Formation of transfer products from soybean arabinogalactan and glycerol by endo-1,4-β-D-galactanase from Penicillium citrinum was described.The amount of transfer products depended on the glycerol concentration.About 50percent of the galactose residues which could be liberated from the polysaccharide by the enzyme were transferred to glycerol at an acceptor concentration of 2.5percent (w/v).Transfer products with various polymerization degrees were accumulated at the beginning of the reaction and then those with higher polymerization degrees were degraded gradually.At a final stage of the reaction, two transfer products in addition to two hydrolysis products (galactose and galactobiose) were mainly accumulated.The two transfer products were isolated and their structures were examined.They were 2-O-β-D-galactosyl glycerol and O-β-D-galactosyl-(14)-O-β-D-galactosyl-(12)glycerol.
