Synthesis of 2-C-Methyl-D-erythritol and 2-C-Methyl-L-threitol; Determination of the Absolute Configuration of 2-C-Methyl-1,2,3,4-butanetetrol Isolated from Phlox sublata L

2-C-Methyl-D-erythritol (A) and 2-C-methyl-L-threitol (B) were respectively synthesized from D-glucose and D-galactose. The 2-C-methyl-1,2,3,4-butanetetrol compound (C) recently isolated from Phlox sublata L was confirmed to be A by comparing the CD and ¹H-NMR spoectra of its tri-O-benzoate with those of A and B.     

Pectin Isolated from the Midrib of Leaves of Nicotiana tabacum

A pectin isolated from tobacco midrib contained residues of d-galacturonic acid (83.7%), L-rhamnose (2.2%), l-arabinose (2.4%) and d-galactose (11.2%) and small amounts of d-xylose and d-glucose. Methylation analysis of the pectin gave 2, 3, 5-tri- and 2, 3-di-O-methyl-l-arabinose, 3, 4-di- and 3-O-methyl-l-rhamnose and 2, 3, 6-tri-O-methyl-d-galactose. Reduction with lithium aluminum hydride of the permethylated pectin gave mainly 2, 3-di-O-methyl-d-galactose and the above methylated sugars. Partial acid hydrolysis gave homologous series of β-(1 → 4)-linked oligosaccharides up to pentaose of d-galactopyranosyl residues, and 2-O-(α-d-galactopyranosyluronic acid)-l-rhamnose, and di- and tri-saccharides of α-(1 → 4)-linked d-galactopyranosyluronic acid residues.

These results suggest that the tobacco pectin has a backbone consisting of α-(1 → 4)-linked d-galactopyranosyluronic acid residues which is interspersed with 2-linked l-rhamnopyranosyl residues. Some of the l-rhamnopyranosyl residues carry substituents on C-4. The pectin has long chain moieties of β-(1 → 4)-linked d-galactopyranosy] residues.     

Structure of Cell Wall Polysaccharide Isolated from Cotyledon of Tora-bean (Phaseolus vulgaris)

The cell wall polysaccharide of cotyledon of Tora-bean (Phaseolus vulgaris), which surrounds starch granules, was isolated from saline-extraction residues of homogenized cotyledon, as alkali-insoluble fibrous substance. Alkali-insoluble residue, which had been treated with α-amylase (Termamyl), had a cellulose-like matrix under the electron microscope. It was composed of l-arabinose, d-xylose, d-galactose and d-glucose (molar ratio, 1.0: 0.2: 0.1: 1.2) together with a trace amount of l-fucose. Methylation followed by hydrolysis of the polysaccharide yielded 2, 3, 5-tri-O-methyl-l-arabinose (3.3 mol), 2, 3, 4-tri-O-methyl-d-xylose (1.0 mol), 2, 3-di-O-methyl-l-arabinose (3.7 mol), 3, 4-di-O-methyl-d-xylose (1.0 mol), 2-O-methyl-l-arabinose and 2, 3, 6-tri-O-methyl-d-glucose (12.7 mol), 2, 6-di-O-methyl-d-glucose (1.2 mol) and 2, 3-di-O-methyl-d-glucose (1.0 mol).

Methylation analysis, Smith degradation and enzymatic fragmentation with cellulase and α-l-arabinofuranosidase showed that the l-arabinose-rich alkali-insoluble polysaccharide possesses a unique structural feature, consisting of β-(1 → 4)-linked glucan backbone, which was attached with side chains of d-xylose residue and β-d-galactoxylose residue at O-6 positions and α-(1 → 5)-linked l-arabinosyl side cains (DP=8) at O-3 positions of β-(1 → 4)-linked d-glucose residues, respectively.     

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).     

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.     

Screening of biologically active monosaccharides: growth inhibitory effects of d-allose,d-talose,and l-idose against the nematode Caenorhabditis elegans

We compared the growth inhibitory effects of all aldohexose stereoisomers against the model animal Caenorhabditis elegans. Among the tested compounds, the rare sugars d-allose (d-All), d-talose (d-Tal), and l-idose (l-Ido) showed considerable growth inhibition under both monoxenic and axenic culture conditions. 6-Deoxy-d-All had no effect on growth, which suggests that C6-phosphorylation by hexokinase is essential for inhibition by d-All.     

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.     

Biosynthesis of Biotin-vitamers from Pelargonic Acid by Pseudomonas sp.

Influence of positional and stereoisomers of methylproline on the biosynthesis of neoviridogrisein (NVG) by Streptomyces griseoviridus P8648 was investigated. 3-(dl-cis + trans)- and 5-(d-cis + l-trans)-Methylprolines inhibited NVG synthesis, but they did not affect the cell growth. When these imino acids were added to cultures of S. griseoviridus P8648, there occurred no production of NVG homologues. In the presence of 4-methylproline (d-cis + l-trans), the organism synthesized a new NVG, designated NVG-MP, in which the imino acid moiety was replaced by 4-methylproline (d-cis). The antimicrobial activity of NVG-MP was compared with those of NVG II and viridogrisein (VG).     

A Growth Factor for Malo-lactic Fermentation Bacteria

A growth factor (TJF) for a malo-lactic fermentation bacterium has been isolated from tomato juice, and found to be a β-glucoside. The NMR spectra of TJF and its acetate revealed that the glucosyl residue linked to the hydroxyl group at C-2′ or C-4′ of d- or l-pantothenic acid moiety. Then, 2′-O-(β-d-glucopyranosyl)-dl-pantothenic acid (I), 4′-O-(β-d-glucopyranosyl)-dl-pantothenic acid (II) and 4′-O-(β-d-glucopyranosyl)-d(R)-pantothenic acid (II-a) were synthesized, and Il-a and 4′-O-(β-d-glucopyranosyl)-l-pantothenic acid (II-b) were obtained by the optical resolution of the acetate of II. Among the above compounds, II-a was identical with natural TJF regarding to the biological activity, NMR and ORD spectra, and thin-layer chromatography.     

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.     

Isolation of Permethylated Dicarbonyl Sugar Derivatives from Polysaccharides

Oxidation of methyl trimethyl glucopyranosides which were obtained by methanolysis of permethylated cellulose, laminarin, and dextran, was performed with dimethyl sulfoxide (DMSO)-phosphorus pentoxide to afford the corresponding ulose derivatives, methyl 2,3,6-tri-O-methyl-d-xylo-hexopyranosid-4-ulose, methyl 2,4,6-tri-O-methyl-d-ribo-hexopyranosid-3-ulose, and methyl 2,3,4-tri-O-methyl-d-gluco-hexodialdo-l,5-pyranoside, respectively, in good or moderate yields. As a new type of derivatives for the linkage analysis of polysaccharides the chromatographic and spectrometric properties of 2,4-dinitrophenylhydrazone of the ulose derivatives were investigated.     

Synthesis of Certain Disaccharides Containing a α-or β- Rhamnopyranosidic Group and the Substrate Specificity of α-l-Rhamnosidase from Aspergillus niger

To investigate the substrate specificity of α-l-rhamnosidase from Aspergillus niger, the following seven substrates were synthesized: methyl 3-O-α-l-rhamnopyranosyl-α-d-mannopyranoside (1), methyl 3-O-α-l-rhamnopyranosyl-α-l-xylopyranoside (2), methyl 3-0-α-l-rhamnopyranosyl-α-l-rhamnopyranoside (3), methyl 4-0-α-l-rhamnopyranosyl-α-d-galactopyranoside (4), methyl 4-O-α-l-rhamnopyranosyl-α-d-mannopyranoside (5), methyl 4-0-α-l-rhamnopyra-nosyl-α-d-xylopyranoside (6), and 6-0-β-l-rhamnopyranosyl-d-mannopyranose (7). Compounds 1~6 were well-hydrolyzed by the crude enzyme, but 7 was unaffected.     

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.     

2-Methylcitrate Dehydratase,a New Enzyme Functioning at the Methylcitric Acid Cycle of Propionate Metabolism

2-Methylcitrate dehydratase (2-methylcitrate hydro-lyase), a new enzyme functioning at the methylcitric acid cycle of propionyl-CoA oxidation, was present in the cell-free extract of Yarrowia (Saccharomycopsis) lipolytica. The enzyme was separated from the usual aconitate hydratase (EC 4.2.1.3) of the yeast with DEAE-Sephadex A-50 column chromatography. The enzyme was able to catalyze a reversible reaction between 2-methylcitrate and 2-methyl-cis-aconitate, but showed no activity on threo-d_s-2-methylisocitrate, citrate, cis- or trans-aconitate, threo-d_s-, threo-DL- or erythro-l_s-isocitrate, DL-homocitrate or other hydroxy-acids tested.

In contrast, the other enzyme fraction separated as aconitate hydratase by chromatography showed no activity on synthetic 2-methylcitrate, but was able to catalyze strongly a reversible reaction between 2-methyl-cis-aconitate and threo-d_s-2-methylisocitrate.

From these findings, the previously proposed cycle sequence was revised at the following broken arrows: propionyl-CoA+oxaloacetate → (CoASH+) 2-methylcitrate ? 2-methyl-cis-aconitate ? threo-d_s-2-methylisocitrate → pyruvate+succinate (→→oxaloacetate).

2-Methylcitrate dehydratase showed maximum activity at pH 6.5 to 7.0 and at 25 to 40°C. The enzyme was stable at temperatures up to 40°C and at pH 6.5 to 7.5, but labile in Tris-HCl buffer. The synthesis of this enzyme was constitutive in this yeast, although it was slightly repressed by glucose.     

Synthesis of 3,6-di-O-Methylglucosyl Disaccharides with Methyl 3-(p-Hydroxyphenyl)propionate as a Linker Arm and Their Use in the Serodiagnosis of Leprosy

The disaccharide, 2,3-di-O-methyl-4-O-(3,6-di-O-methyl-β-d-glucopyranosyl)-l-rhamno-pyranose, the distal segment of phenolic glycolipid I, that is a specific antigen from Mycobacterium leprae, and some related disaccharides were synthesised as the glycosides of methyl 3-(p-hydroxyphenyl)propionate. The methyl 3-(p-hydroxyphenyl)propionate was coupled with 2,3,4-tri-O-acetyl-l-rhamnosyl bromide, deacetylated, acetonated, coupled with 2,4,6-tri-O-acetyl-3-O-methyl-d-glucosyl bromide, and converted into a variety of p-(2-methoxycarbonylethyl)phenyl 4-O-(3,6-di-O-methyl-d-glucopyranosyl)-containing disaccharides that are amenable to ready conjugation with protein carriers, thereby providing neo-glycoconjugates for the specific serodiagnosis of leprosy.     

The Acceptor Specificity of Amylomaltase from Escherichia coli IFO 3806

The acceptor specificity of amylomaltase from Escherichia coli IFO 3806 was investigated using various sugars and sugar alcohols. d-Mannose, d-glucosamine, N-acetyl- d-glucosamine, d-xylose, d- allose, isomaltose, and cellobiose were efficient acceptors in the transglycosylation reaction of this enzyme. It was shown by chemical and enzymic methods that this enzyme could transfer glycosyl residues only to the C4-hydroxyl groups of d-mannose, iY-acetyl- d-glucosamine, d-allose, and d-xylose, producing oligosaccharides terminated by 4–0-α-d-glucopyranosyl-d-mannose, 4–0-α-d-glucopyranosyl-yV-acetyl-d-glucosamine, 4-O-α-d-glucopyranosyl-d-allose, and 4–0-α-d-gluco- pyranosyl-d-xylose at the reducing ends, respectively.     

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.     

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.     

The Structure of Arabinoxylan and Arabinoglucuronoxylan Isolated from Rice Endosperm Cell Wall

A neutral and an acidic arabinoxylan fraction (H-l and H-2) were obtained from rice endosperm cell wall. The results of methylation analysis and partial hydrolysis of these fractions showed that both of them have highly branched structures in which approximately 6 out of 7 (H-l) and 5 out of 6 (H-2) of the (1→4)-linked d-xylose residues are branched. Most of the side chains in H-l consists of single α-l-arabinofuranose residues, whereas some of them in H-2 were substituted with α-d-glucuronic acid or 4-O-methyl-α-d-glucuronic acid residues, both attached to the O-2 position of d-xylose residues. These highly branched arabinoxylans are not readily hydrolyzed by an endoxylanase of Streptomyces sp.     

Synthesis of 7-Deoxy-d-glycero-d-gluco-heptose (SF-666A)

The synthesis of 7-deoxy-d-glycero-d-gluco-heptose (1) from 3,5-O-benzylidene-1,2-O-isopropylidene-α-d-glucofuranose (2) is described. Oxidation of compound (2) afforded 3,5-O-benzylidene-1,2-O-isopropylidene-α-d-gluco-hexodialdo-1,4-furanose (3), which was then treated with methylmagnesium iodide to give 3,5-O-benzylidene-1,2-O-isopropylidene-7-deoxy-α-d-glycero-d-gluco-heptose (4) and its l-glycero-d-gluco isomer (5). Hydrolysis of (4) produced compound (1), which was identical with natural SF-666 A, a fermentation product of Streptomyces setonensis nov. sp.