title: Acetolysis of Pichia pastoris IFO 0948 strain mannan containing alpha-1,2 and beta-1,2 linkages using acetolysis medium of low sulfuric acid concentration.
abstract: To obtain manno-oligosaccharides containing beta-1,2-linked nonreducing terminal groups from the mannan of Pichia pastoris IFO 0948 strain by acetolysis, an attempt was made to establish the reaction conditions under which cleavage of the alpha-1,6 linkage took place preferentially leaving manno-oligosaccharides composed largely of beta-1,2 linkages. By the action of an ordinary acetolysis medium, a 10/10/1 (v/v) mixture of acetic anhydride, acetic acid, and sulfuric acid at 40 degrees C for 13 h or at 25 degrees C for 120 h, the O-acetyl derivative of this mannan gave mannose, mannobiose, mannotriose, and mannopentaose. However, treatment of the same O-acetyl mannan with a 50/50/1 (v/v) acetolysis medium at 40 degrees C for 15 h gave a mannotetraose in addition to mannose, mannobiose, mannotriose, and mannopentaose. Use of a 100/100/1 (v/v) acetolysis medium at 40 degrees C for 36 h gave a more satisfactory result, a mixture of oligosaccharides, from mannose to mannopentaose, which contained more mannotetraose than mannopentaose. Because both mannotetraose and mannopentaose contained alpha-1,2 and beta-1,2 linkages, it was concluded that an acetolysis medium containing a low concentration of sulfuric acid, up to 0.5% (v/v), facilitates the preferential cleavage of the alpha-1,6 linkage, leaving manno-oligosaccharides containing the beta-1,2 linkage which was found to be labile to the action of the 10/10/1 (v/v) acetolysis medium.
mesh_terms: D000107:Acetylation; D002473:Cell Wall / Q000032:analysis; D055598:Chemical Phenomena; D002621:Chemistry; D006868:Hydrolysis; D009682:Magnetic Resonance Spectroscopy; D008351:Mannans / Q000302:isolation & purification*; D008358:Mannose / Q000302:isolation & purification*; D008745:Methylation; D009844:Oligosaccharides / Q000302:isolation & purification*; D004718:Saccharomycetales / Q000032:analysis*; D013464:Sulfuric Acids
chemical_list: D008351:Mannans; D009844:Oligosaccharides; D013464:Sulfuric Acids; C039922:mannotetraose; C048068:mannopentaose; D008358:Mannose