Synthesis of mannosyl cellobiose diphosphate prenol in Acetobacter xylinum
The enzymatic synthesis of a β-mannosyl (1 → 3) β-glucosyl (1 → 4) α-glucose-1-pyrophosphate-prenol (allylic) by Acetobacter xylinum preparations is described. Glucose pyrophosphate lipid, already known to be formed from UDP-glucose and endogenous phosphate lipid, is demonstrated to accept another g...
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1980
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| Acceso en línea: | https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00039861_v204_n2_p434_Couso http://hdl.handle.net/20.500.12110/paper_00039861_v204_n2_p434_Couso |
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| Sumario: | The enzymatic synthesis of a β-mannosyl (1 → 3) β-glucosyl (1 → 4) α-glucose-1-pyrophosphate-prenol (allylic) by Acetobacter xylinum preparations is described. Glucose pyrophosphate lipid, already known to be formed from UDP-glucose and endogenous phosphate lipid, is demonstrated to accept another glucose from UDP-glucose to give a cellobiose pyrophosphate lipid. The latter in turn accepts mannose from GDP-mannose to form a mannosyl cellobiose pyrophosphate lipid. The structure of the trisaccharide and the way it is linked to the lipid moiety were established by enzymatic and chemical methods such as mild alkaline and acid hydrolysis, phenol treatment, partial acid hydrolysis and acetolysis, periodate oxidation, borohydride reduction, and treatments with glycosidases. The α-unsaturated, polyprenolic nature of the lipid was inferred from and confirmed by the reaction between UDP-glucose and ficaprenol monophosphate to give glucose pyrophosphate ficaprenol, which had the same properties as the glucose pyrophosphate lipid formed from the endogenous acceptor. The allylic structure proposed for the endogenous acceptor is suggested by the lability to phenol treatment and catalytic reduction of its glycosylated derivatives. The enzyme preparation also synthesizes a β-mannose phosphate prenol (allylic), which does not seem to participate in the trisaccharide synthesis. The possible role of these sugar prenols in the synthesis of exopolysaccharides is considered. © 1980, All rights reserved. |
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