Isolation and Characterization of Oligosaccharides from the Hydrolyzate of Larch Wood Glucomannan with Endo-β-d-Mannanase

The glucomannan isolated from larch holocellulose was hydrolyzed by a purified endo-d-β-mannanase. The products were fractionated by gel filtration on a Polyacrylamide gel in water and partition chromatography on ion exchange resins in 80% ethanol. The following oligosaccharides were isolated and identified: (a) 4-O-β-d-Manp-d-Man, (b) 4-O-β-d-Glcp-d-Man, (c) 4-O-β-d-Glcp-d-Glc, (d) O-β-d-Manp-(1 →4)-O-β-d-Manp-(1 →4)-d-Man, (e) O-β-dGlcp-(l →4)-O-β-d-Manp-(l →4)-d-Man, (f) O-β-d-Manp-(l →4)-Oβ-d-Glcp-(l →4)-d-Man, (g) O-β-d-Manp-(l →4)-O-[α-d-Galp-(l →6)]-d-Man, (h) O-β-d-Manp-(l →4)-O-β-d-Manp-(l →4)-O-β-d-Manp-(l →4)-d-Man, and (i) O-β-d-Glcp-(1 →4)-O-β-d-Manp-(1 →4)-O-β-d-Manp-(1 →4)-d-Man.     

Formation of Three New Trisaccharide-azoxyglycosides by Transglucosylation by Cycad β-Glucosidase

transglucosylation by a β-d-glucosidase from cycad seeds. These azoxyglycosides, named neocycasin H, I, and J, were identified as O-β-d-glucopyranosyl-(1→4)-O-β-d-glucopyranosyl-(l→3)-O-β-d-glucopyranoside of methylazoxymethanol (MAM), O-β-d-glucopyranosyl-(1→3)-[O-β-d-glucopyranosyl-(1→6)]-O-β-d-glucopyranoside of MAM, and O-β-d-glucopyranosyl-(1→3)-[O-β-d-xylopyranosyl-(1→6)]-O-β-d-glucopyranoside of MAM, respectively. On the basis of their structures, the mechanism of the formation of these neocycasins is also discussed.     

Studies on the Chemical Structure of Konjac Mannan

The electrophoretically homogeneous glucomannan isolated from konjac flour was composed of d-glucose and d-mannose residues in the approximate ratio of 1: 1.6. Controlled acid hydrolysis gave 4-O-β-d-mannopyranosyl-d-mannose, 4-O-β-d-mannopyranosyl-d-glucose_T 4-O-β-d-glucopyranosyl-d-glucose(cellobiose), 4-O-β-d-glucopyranosyl-d-mannose(epicellobiose), O-β-d-mannopyranosyl-(1→4)-O-β-d-mannopyranosyl-(1→4)-d-mannose, O-β-d-glucopyranosyl- (1→4)-O-β-d-mannopyranosyl-(1→4)-d-mannose, O-β-d-mannopyranosyl-(1→4)-O-β-d-glucopy- ranosyl-(1→4)-d-mannose and O-β-d-glucopyranosyl-(1→4)-O-β-d-glucopyranosyl-(1→4)-d-mannose.     

Coenzyme Q10 in the Respiratory Chain Linked to Fructose Dehydrogenase of Gluconobacter cerinus

A glucomannan isolated from konjac flour was hydrolyzed with commercially available crude and purified cellulases. The following oligosaccharides were isolated from the hydrolyzate and identified: (a) 4-O-β-d-mannopyranosyl-d-monnose (b) 4-O-β-d-mannopyranosyl-d-glucose (c) O-β-d-mannopyranosyl-(1→4)-O-β-d-mannopyranosyl-(1→4)-d-mannose (d) O-β-d-mannopyranosyl-(1→4)-O-β-d-mannopyranosyl-(1→4)-d-glucose (e) O-β-d-mannopyranosyl-(1→4)-O-β-d-mannopyranosyl-(1→4)-O-β-d-mannopyranosyl-(1→4)-d-mannose (f) O-β-d-mannopyranosyl-(1→4)-O-β-d-mannopyranosyl-(1→4)-O-β-d-mannopyranosyl-(1→4)-d-glucose (g) O-β-d-mannopyranosyl-(1→4)-O-β-d-mannopyranosyl-(1→4)-O-β-d-mannopyranosyl-(1→4)-O-β-d-mannopyranosyl-(1→4)-d-glucose (h) 4-O-β-d-glucopyranosyl-d-glucose(cellobiose) (i) 4-O-β-d-glucopyranosyl-d-mannose (epicellobiose) (j) O-β-d-glucopyranosyl-(1→4)-O-β-d-mannopyranosyl-(1→4)-d-mannose. Of these saccharides, (h), (i) and (j) were isolated from the hydrolyzate by purified cellulase, while (g) was isolated from the hydrolyzate by crude cellulase. The others were all present in the hydrolyzates both by crude and by purified cellulases.     

Cyclic (1→2)-β-d-Glucan-hydrolyzing Enzymes from Acremonium sp. 15 Purification and Some Properties of Endo-( 1 → 2)-α-d-glucanase and β-d-Glucosidase

Acremonium sp. 15 a fungus isolated from soil, produces an extracellular enzyme system degrading cyclic (1→2)-β-d-glucan. This enzyme was found to be a mixture of endo-(1→2)-β-d-glucanase and β-d-glucosidase. The (1→2)-β-d-glucanase was purified to homogeneity shown by disc-electrophoresis after SP-Sephadex column chromatography, Sephadex G-75 gel filtration, and rechromatography on SP-Sephadex. The molecular weight of the enzyme was 3.6 × 10⁴ by SDS-polyacrylamide gel electrophoresis. The isoelectric point of the enzyme was pH 9.6. The enzyme was most active at pH 4.0—4.5, and stable up to 40°C in 20 mm acetate buffer (pH 5.0) for 2 hr of incubation. This enzyme hydrolyzed only (l→2)-β-d-glucan and did not hydrolyze laminaran, curdlan, or CM-cellulose. The hydrolysis products from cyclic (1→2)-β-d-glucan were mainly sophorose.

The β-d-glucosidase was purified about 4000-fold. The rate of hydrolysis of the substrates by this β-d-glucosidase decreased in the following order: β-nitrophenyl-β-d-glucoside, sophorose, phenyl-β-d-glucoside, laminaribiose, and salicin. This enzyme has strong transfer action even at the low concentration of 0.75 mm substrate.     

Structure of Carbohydrate Moiety of Asterosaponin A

Partial acid hydrolysis of asterosaponin A, a steroidal saponin, afforded two new disaccharides in addition to O-(6-deoxy-α-d-glucopyranosyl)-(l→4)-6-deoxy-d-glucose which has been characterized in the preceding paper. The formers were demonstrated as O-(6-deoxy-α-d-galactopyranosyl)-(1→4)-6-deoxy-d-glucose and O-(6-deoxy-α-d-galactopyranosyl)-(l→4)-6-deoxy-d-galactose, respectively.

Accordingly, the structure of carbohydrate moiety being composed of two moles each of 6-deoxy-d-galactose and 6-deoxy-d-glucose, was established as O-(6-deoxy-α-d-galactopyranosyl)-(l→4)-O-(6-deoxy-α-d-galactopyranosyl)-(l→4)-O-(6-deoxy-α-d-glucopyranosyl)-(l→4)-6-deoxy-d-glucose, which is attached to the steroidal aglycone through an O-acetal glycosidic linkage.     

An Endo-(l → 6)-β-d-glucanase of Flavobacterium M64 Hydrolyzing the Octasaccharide Repeating Unit of Succinoglycan to Two Tetrasaccharides

An endo-(l → 6)-β-d-glucanase capable of hydrolyzing octasaccharide to two tetrasaccharides was isolated from cells of Flavobacterium M64. The octasaccharide represents the repeating unit of succinoglycan (SG-D). One tetrasaccharide was composed of d-glucose, succinic acid and pyruvic acid (4:1:1, molar ratio), and the other was composed of d-glucose and d-galactose (3:1, molar ratio). This enzyme hydrolyzed the (l → 6)-β-d-glucosidic linkage adjacent to the (1 → 6)-linked β-d-glucose residue in the octasaccharide repeating unit of succinoglycan and also hydrolyzed the octasaccharide repeating units of similar polysaccharides produced by many strains of Agrobacterium and Rhizobium species.     

A Bitter Principle of Asparagus: Isolation and Structure of Furostanol Saponin in Asparagus Storage Root

During an examination of components contributing to the bitter taste of asparagus bottom cut (Asparagus officinalis L.), two new furostanol saponins were isolated from roots extractives. Their chemical structures were established as 5β-furostane-3β,22,26 triol-3-O-β-d-glucopyranosyl (1→2)-β-d-glucopyranoside 26-O-β-d-glucopyranoside and 5β-furostane-3β,22,26 triol-3-O-β-d-glucopyranosyl (1→2) [β-d-xylopyranoxyl (1→4)]-β-d-glucopyranoside 26-O-β-d-glucopyranoside respectively.     

A New Synthesis of (—)-exo-Brevicomin

Rubusoside derivatives by transgalactosylation of various β-galactosidases were isolated and their structures were analyzed. Escherichia coli β-galactosidase produced mainly 13-O-β-d-glucosyl-19-O-[β-d-galactosyl-(1→6)-β-d-glucosyl]-steviol (RGal-2). Bacillus circulans β-galactosidase produced mainly 13-O-β-d-glucosyl-19-O-[β-d-galactosyl-(1→4)-β-d-glucosyl]-steviol (RGal-1a) in the early stage of the reaction and then produced 13-O-[β-d-galactosyl-(1→4)-β-d-glucosyl]-19-O-β-d-glucosyl-steviol (RGal-1b). With decreasing the amount of these products (RGal-1a and RGal-1b), RGal-2 was produced.     

A Simple Transductional Method for Construction of Adenylate- cyclase or cAMP Receptor Protein-deficient Mutants of Escherichia coli K-12

The substrate specificity of α-d-xylosidase from Bacillus sp. No. 693–1 was further investigated. The enzyme hydrolyzed α-1,2-, α-1,3-, and α-1,4-xylobioses. It also acted on some heterooligosaccharides such as O-α-d-xylopyranosyl-(1→6)-d-glucopyranose, O-α-d-xylopyranosyl-(1→6)-O-β-d-glucopyranosyl-(1→4)-d-glucopyranose, O-α- d-xylopyranosyl-(1→6)-O-d-glucopyranosyl-(1→4)-O-[α-d-xylopyranosyl-(1→6)]-d-glucopyranose, and O-α-d-xylopyranosyl-(1→3)-l-arabinopyranose. The enzyme was unable to hydrolyze tamarinde polysaccharides although it could hydrolyze low molecular weight substrates with similar linkages.     

Glycolipids Isolated from Spirulina maxima: Structure and Fatty Acid Composition

Several glycolipids were isolated from Spirulina maxima, an edible blue-green algae, by systematic fractionation with different solvents. Structural investigation by using methylation, GC-MS, and enzymic techniques indicated that the major glycolipids are O-β-d-galactosyl-(1→l′)-2′, 3′-di-O-acyl-d-glycerol, O-α-d-galactosyl-(l-→6)-O-β-d-galactosyl-(1→l′)-2′,3′-di-O-acyl-d-glycerol and 6-sulfo-O-α-quinovosyl-(l→l′)-2′, 3′-di-O-acyl-d-glycerol. Main fatty acid components of these glycolipids were identified as palmitic acid and linoleic or linolenic acid. Based on-these fatty acid compositions, Spirulina glycolipids were compared with those in higher plants.     

Structure of Oligosaccharides Obtained by Controlled Degradation of Mung Bean Xyloglucan with Acid and Aspergillus oryzae Enzyme Preparation

A xyloglucan (MBXG) from the cell walls of etiolated mung bean hypocotyls was characterized by analyzing the fragment oligosaccharides from controlled degradation products of the polymer with acid and enzyme.

Cellobiose, cellotriose and cellotetraose were isolated from the partial acid hydrolyzate of MBXG. Isoprimeverose (6-O-α-d-xylopyranosyl-d-glucopyranose) and a pentasaccharide, α-l-fucosyl-(1 → 2)-β-d-galactosyl-(1 → 2)-α-d-xylosyl-(1 → 6)-β-d-glucosyl-(1 → 4)-d-glucose, were isolated from the hydrolyzate of MBXG with an Asp. oryzae enzyme preparation.     

Effects of Metal Ions on Cattle Liver Phosphoenolpyruvate Carboxykinase Activity in Vitro

A plant glycosphingolipid, O-(β-d-mannopyranosyl)-(l → 4)-O-(β-d-glucopyranosyl)-(l → l)-(2S,3S,4R)-4-hydroxy-N-tetracosanoylsphinganine 1, and the stereoisomer, O-(α-d-mannopyranosyl)-(1 → 4)-O-(β-d-glucopyranosyl)-(l → l)-(2S,3S,4R)-4-hydroxy-N-tetracosanoylsphinganine 6, were synthesized in a stereo- and regio-controlled way.     

The Mutational Effect of Ile58 at Subsite C in Hen Egg-White Lysozyme on Substrate Binding,Enzymatic Activity,and Protein Stability

Partial acid hydrolysis of Saccharomyces cerevisiae mannan gave 2-O-α-d-Manp-d-Man (1), 3-O-α-d-Manp-d-Man (2), 6-O-α-d-Manp-d-Man (3), O-α-d Manp-(1→2)O-α-d-Manp-(1→2)-d-Man (4), O-α-d-Manp-(1→2)-O-α-d-Manp-(1→6)-d-Man (5), O-α-d Manp-(1→6)-6-O-α-d-Manp-(1→6)-d-Man (6), O-α-d Manp-(1→2)-O-α-d-Manp-(1→2)-6-O-α-d-Manp-(1→6)-d-Man (7), O-α-d-Manp-(1→2)-O-α-d-Manp-(1→6)-O-α-d-Manp-(1→6)-d-Man (8), and O-α-d-Manp-(1→6)-O-[α-d-Manp-(1→2)]-O-α-d-Manp-(1→6)-d-Man (9).     

Effects of Dietary Level of Iron and Ascorbic Acid on Cadmium Toxicity in Rats

The transxylosylation reaction products of β-xylosidase-1, excreted by Penicillium wortmanni IFO 7237 using β-(1→4)-xylobiose as substrate, have been separated by chromatography on activated charcoal into four fractions, designated as P-1, P-2, P-3, and P-4, respectively. They were further purified by preparative paper chromatography. The characterization and structural analysis were done by measurement of the degree of polymerization (DP) and specific rotation followed by methylation analysis. Moreover, the enzymatic structural analysis of transxylosylation products, with high performance liquid chromatography (HPLC), allowed the confirmation of each structure. The first product, P-1, was β-(1→3)-xylobiose and the second, P-2, was β-(1→4)-xylotriose, but, P-3 was O-β-d-xylopyranosyl-(1→3)-O-β-d-xylopyranosyl-(1→4)-d-xylopyranose or isomeric xylo-triose and P-4 was assumed to be O-β-d-xylopyranosyl-(1→4)-[O-β-d-xylopyranosyl-(1→3)]-O-β-d-xylopyranosyl-(1→4)-d-xylopyranose.     

A New Glucuronide Saponin from Tea Leaves (Camellia sinensis var. sinensis)

A new glucuronide saponin (1) was isolated as its methyl ester (2) from the leaves of Camellia sinensis var. sinensis. On the basis of its spectral data and the results of chemical degradation, the structure was elucidated to be 3-O-1{β-d-galactopyranosyl(l → 2)-[β-d-xylopyranosyl(1 → 2)-α-l-arabinopyranosyl(1 → 3)]-β-d-glucuronopyranosyl}-21-O-cinnamoyl-16,22–di-O-acetylbarringtogenol C.     

Variation of Protein among Eleven Varieties of Common Bean (Phaseolus vulgaris)

The acylated, amidated and esterified derivatives of N-acetylglucosaminyl-α(1 → 4)-N-acetylmuramyl tri- and tetrapeptide were synthesized and examined as to their protective effect on pseudomonal infection in the mouse and pyrogenicity in the rabbit. Modifications of the terminal end function of the peptide moieties in their molecules caused enhancement of resistance to pseudomonal infection and reduction of pyrogenicity. Among the compounds tested, sodium N-acetylglucosaminyl-β(1 → 4)-N-acetylmuramyl-l-alanyl-d-isoglutaminyl-(l)-stearoyl-(d)-meso-2,6-diaminopimelic acid-(d)-amide and sodium N-acetylglucosaminyl-β(1 → 4)-N-acetylmuramyl-l-alanyl-d-isoglutaminyl-(l)-stearoyl-(d)-meso-2,6-diaminopimelic acid-(d)-amide-(l)-d-alanine were found to be advantageous and conceivably worthwhile for further investigation as immunobiologically active compounds.     

Structure and Bitterness in Flavanone Glycosides

Naringenin-7-β-kojibioside, -7-β-sophoroside, -7-[α-d-galactosyl(l→2)β-d-glucoside], -7-[β-d-glucosyl(l→2)β-d-galactoside], and also hesperetin-7-β-kojibioside and -7-β-sophoroside were prepared by the coupling of naringenin or hesperetin with the α-acetobromo derivatives of the appropriate disaccharides, followed by saponification.

Their relative bitterness values were discussed in comparison with naringin and neo-hesperidin.     

Enzymic Production of Sweet Stevioside Derivatives: Transglucosylation by Glucosidases

For the purpose of improving sweetness and a further study on the structure-sweetness relationship of steviol glycosides, transglycosylation of stevioside by a variety of commercial glucosidases was investigated. It was revealed that two α-glucosidases gave glucosylated products. Transglucosylation of stevioside by Pullulanase and pullulan exclusively afforded three products, 13-O-[β-maltotriosyl-(1 → 2)-β-d-glucosyl]-19-O-β-d-glucosyl-steviol (1), 13-O-[β-maltosyl-(1 → 2)-β-d-glucosyl]-19-O-β-d-glucosyl-steviol (2) and 13-O-β-sophorosyl-19-O-β-maltotriosyl-steviol (3). All of these products have already been obtained by trans-α-1,4-glucosylation of stevioside by the cyclodextrin glucano-transferase starch system, and 1 and 2 have been proven to be tasty and potent sweeteners. Transglucosylation of stevioside by Biozyme L and maltose afforded three new products, 4, 5 and 6, the structures of these compounds being elucidated as 13-O-β-sophorosyl-19-O-β-isomaltosyl-steviol (4), 13-O-β-isomaltosyl(l → 2)-β-d-glucosyl]-19-O-β-d-glucosyl-steviol (5) and 13-O-[β-nigerosyl-(1 → 2)-β-d-glucosyl]-19-O-β-d-glucosyl-steviol (6). A significantly high quality of taste was evaluated for 4.     

Structural Studies on New,Non-reducing Oligosaccharides Produced by Rhizobium meliloti J7017

Three non-reducing oligosaccharides were isolated from the fraction of cyclic (1→2)-β-d-glucan of Rhizobium meliloti J7017 by reversed-phase chromatography and paper chromatography. Methylation and ¹H-NMR analyses indicated that they were α-d-glucopyranosyl α-kojitrioside, α-d-glucopyranosyl α-kojitetraoside, and α-d-glucopyranosyl α-kojipentaoside.