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1.
《Bioscience, biotechnology, and biochemistry》2013,77(4):934-936
Pyridoxine (vitamin B6) in Rhizobium is synthesized from 1-deoxy-D-xylulose and 4-hydroxy-L-threonine. To define the pathway enzymatically, we established an enzyme reaction system with a crude enzyme solution of R. meliloti IFO14782. The enzyme reaction system required NAD+, NADP+, and ATP as coenzymes, and differed from the E. coli enzyme reaction system comprising PdxA and PdxJ proteins, which requires only NAD+ for formation of pyridoxine 5′-phosphate from 1-deoxy-D-xylulose 5-phosphate and 4-(phosphohydroxy)-L-threonine. 相似文献
2.
Yoshitami Ohashi Shuzo Kawabe Takeo Kono Yukio Ito 《Bioscience, biotechnology, and biochemistry》2013,77(10):2379-2385
From the methanolysis product of the antibiotic YA–56 X (Zorbamycin) and Y belonging to phleomycin-bleomycin group, two monosaccharides and one disaccharide were isolated as their fully acetylated derivatives. The structures of these compounds were determined to be methyl 2,3,4-tri-O-acetyl-6-deoxy-β-L-gulopyranoside, methyl 2,4,6-tri-O-acetyl-3-O-carbamoyl-α-D-mannopyranoside and methyl 2-O-(2,4,6-tri-O-acetyl-3-O-carbamoyl-α-D-mannopyranosyl)-3,4-O-0-acetyl-6-deoxy-β-L-“gulopyranoside,Based on these results, it was concluded that 2-O-(3-O-carbamoyl-α-D-mannosyl)-6-deoxy-L-gulose is present as a sugar moiety of the antibiotic YA–56. 相似文献
3.
《Bioscience, biotechnology, and biochemistry》2013,77(12):2578-2586
The cepA putative gene encoding a cellobiose phosphorylase of Thermotoga maritima MSB8 was cloned, expressed in Escherichia coli BL21-codonplus-RIL and characterized in detail. The maximal enzyme activity was observed at pH 6.2 and 80°C. The energy of activation was 74 kJ/mol. The enzyme was stable for 30 min at 70°C in the pH range of 6-8. The enzyme phosphorolyzed cellobiose in an random-ordered bi bi mechanism with the random binding of cellobiose and phosphate followed by the ordered release of D-glucose and α-D-glucose-1-phosphate. The K m for cellobiose and phosphate were 0.29 and 0.15 mM respectively, and the k cat was 5.4 s-1. In the synthetic reaction, D-glucose, D-mannose, 2-deoxy-D-glucose, D-glucosamine, D-xylose, and 6-deoxy-D-glucose were found to act as glucosyl acceptors. Methyl-β-D-glucoside also acted as a substrate for the enzyme and is reported here for the first time as a substrate for cellobiose phosphorylases. D-Xylose had the highest (40 s-1) k cat followed by 6-deoxy-D-glucose (17 s-1) and 2-deoxy-D-glucose (16 s-1). The natural substrate, D-glucose with the k cat of 8.0 s-1 had the highest (1.1×104 M-1 s-1) k cat/K m compared with other glucosyl acceptors. D-Glucose, a substrate of cellobiose phosphorylase, acted as a competitive inhibitor of the other substrate, α-D-glucose-1-phosphate, at higher concentrations. 相似文献
4.
《Bioscience, biotechnology, and biochemistry》2013,77(8):1652-1655
D-Galactosyl-β1→4-L-rhamnose (GalRha) was produced enzymatically from 1.1 M sucrose and 1.0 M L-rhamnose by the concomitant actions of four enzymes (sucrose phosphorylase, UDP-glucose-hexose 1-phosphate uridylyltransferase, UDP-glucose 4-epimerase, and D-galactosyl-β1→4-L-rhamnose phosphorylase) in the presence of 1.0 mM UDP-glucose and 30 mM inorganic phosphate. The accumulation of GalRha in 1 liter of the reaction mixture reached 230 g (the reaction yield was 71% from L-rhamnose). Sucrose and fructose in the reaction mixture were removed by yeast treatment, but isolation of GalRha by crystallization after yeast treatment was unsuccessful. Finally, 49 g of GalRha was isolated from part of the reaction mixture with yeast treatment by gel-filtration chromatography. 相似文献
5.
《Bioscience, biotechnology, and biochemistry》2013,77(10):2106-2109
A simple procedure is described to obtain D- and L-allothreonine (D- and L-aThr). A mixture of N-acetyl-D-allothreonine (Ac-D-aThr) and N-acetyl-L-threonine (Ac-L-Thr) was converted to a mixture of their ammonium salts and then treated with ethanol to precipitate ammonium N-acetyl-L-threoninate (Ac-L-Thr·NH3) as the less-soluble diastereoisomeric salt. After separating Ac-L-Thr·NH3 by filtration, Ac-D-aThr obtained from the filtrate was hydrolyzed in hydrochloric acid to give D-aThr of 80% de, recrystallized from water to give D-aThr of >99% de. L-aThr was obtained from a mixture of the ammonium salts of Ac-L-aThr and Ac-D-Thr in a similar manner. 相似文献
6.
《Bioscience, biotechnology, and biochemistry》2013,77(11):2244-2246
We have developed a new enzymatic assay for determining L-cysteine concentration. The method involves the use of βC-S lyase from Streptococcus anginosus, which catalyzes the α,β-elimination of L-cysteine to hydrogen sulfide, pyruvate, and ammonia. The production of pyruvate is measured by D-lactate dehydrogenase and NADH. The decrease in NADH was proportional to the L-cysteine concentration up to 1.0 mM. When serum samples were used, within-day and day-to-day coefficient variations were below 4%. This method is simple, and can easily and reliably be used for accurate determination of L-cysteine concentration in serum or other samples. 相似文献
7.
《Bioscience, biotechnology, and biochemistry》2013,77(12):2099-2103
In order to clarify the substrate specificity of the α-L-mannosidase activity of naringinase (Sigma), the following disaccharides and phenol glycosides were freshly prepared: methyl 2-O-(α-L-mannopyranosyl)β-D-glucoside (1), methyl 3-O-(α-L-mannopyranosyl)-α-D-glucoside (2), methyl 4-O-(α-L-mannopyranosyl)-α-D-glucoside (3), methyl 5-O-(α-L-mannopyranosyl)-β-D-glucoside (4), methyl 6-O-(α-L-mannopyranosyl)-α-Dglucoside (5), 6-O-(α-L-mannpyranosyl)-D-galactose (6), p-nitrophenyl α-L-mannoside (7), and 4-methyl umbelliferone α-L-mannoside (8).These compounds, except for 3 and 5, were hydrolyzed with naringinase. 相似文献
8.
《Bioscience, biotechnology, and biochemistry》2013,77(9):1386-1391
Bacillus stearothermophilus CGTase had a wider acceptor specificity than Bacillus macerans CGTase did and produced large amounts of transfer products of various acceptors such as D-galactose, D-mannose, D-fructose, D- and L-arabinose, d- and L-fucose, L-rhamnose, D-glucosamine, and lactose, which were inefficient acceptors for B. macerans CGTase. The main component of the smallest transfer products of lactose was assumed to be α-D-glucosyl O-β-D-galactosyl-(l→4)-β-D-glucoside. 相似文献
9.
《Bioscience, biotechnology, and biochemistry》2013,77(10):2133-2136
A correlation between the quantitative changes in L-methionine analogs, the ratio of D-serine/L-serine during the pupal stage, and metamorphosis was observed. The glycoside appearing at low blood sugar values during the pupal stage was isolated and characterized as D-glucosyl-L-tyrosine. 1H-NMR indicated the appearance and increase of this glycoside, and Mirrorcle Ray CV4 equipment was used to take X-ray pictures of the pupal bodies. The results indicate that γ-cyclic di-L-glutamate and L-methionine sulfone might be concerned with ammonia assimilation in the pupae, and that D-glucosyl-L-tyrosine served as a switch for the fatty acid (pupal oil) dissimilation hybrid system. 相似文献
10.
Toshio Nikaido Shigeo Tomioka Michio Matsuhashi 《Bioscience, biotechnology, and biochemistry》2013,77(12):2639-2640
2,3-Diaminopropionate ammonia-lyase (DAPAL), which catalyzes α,β-elimination of 2,3-diaminopropionate regardless of its stereochemistry, was purified from Salmonella typhimurium. We cloned the Escherichia coli ygeX gene encoding a putative DAPAL and purified the gene product to homogeneity. The protein obtained contained pyridoxal 5′-phosphate and was composed of two identical subunits with a calculated molecular weight of 43,327. It catalyzed the α,β-elimination of both D- and L-2,3-diaminopropionate. The results confirmed that ygeX encoded DAPAL. The enzyme acted on D-serine, but its catalytic efficiency was only 0.5% that with D-2,3-diaminopropionate. The enzymologic properties of E. coli DAPAL resembled those of Salmonella DAPAL, except that L-serine, D- and L-β-Cl-alanine were inert as substrates of the enzyme from E. coli. DAPAL had significant sequence similarity with the catalytic domain of L-threonine dehydratase, which is a member of the fold-type II group of pyridoxal phosphate enzymes, together with D-serine dehydratase and mammalian serine racemase. 相似文献
11.
《Nucleosides, nucleotides & nucleic acids》2013,32(4-7):665-668
Novel D- and L-2′-azido-2′,3′-dideoxy-4′-thionucleosides were synthesized starting from L- and D-xylose via D- and L-4-thioarabitol derivative as key intermediates and evaluated for antiviral activity, respectively. When the final nucleosides were tested against HIV-1, HSV-1, HSV-2, and HCMV, they were found to be only active against HCMV without cytotoxicity up to 100 μg/ml. 相似文献
12.
《Nucleosides, nucleotides & nucleic acids》2013,32(5-8):1117-1118
Abstract The efficient synthesis of oligonucleotides containing 2′-O-β-D-ribofuranosyl (and β-D-ribopyranosyl)nucleosides, 2′-O-α-D-arabinofuranosyl (and α-L-arabinofuranosyl)nucleosides, 2′-O-β-D-erythrofuranosylnucleosides, and 2′-O-(5′-amino-5-deoxy-β-D-ribofuranosyl)nucleosides have been developed. 相似文献
13.
《Bioscience, biotechnology, and biochemistry》2013,77(10):2293-2298
An X-ray crystal structural analysis revealed that (2S,3S)-N-acetyl-2-amino-3-methylpentanoic acid (N-acetyl-L-isoleucine; Ac-L-Ile) and (2R,3S)-N-acetyl-2-amino-3-methylpentanoic acid (N-acetyl-D-alloisoleucine; Ac-D-aIle) formed a molecular compound containing one Ac-L-Ile molecule and one Ac-D-aIle molecule as an unsymmetrical unit. This molecular compound is packed with strong hydrogen bonds forming homogeneous chains consisting of Ac-L-Ile molecules or Ac-D-aIle molecules and weak hydrogen bonds connecting these homogeneous chains in a fashion similar to that observed for Ac-L-Ile and Ac-D-aIle. Recrystallization of an approximately 1:1 mixture of Ac-L-Ile and Ac-D-aIle from water gave an equimolar molecular compound due to its lower solubility than that of Ac-D-aIle or especially Ac-L-Ile. The results suggest that the equimolar mixture of Ac-L-Ile and Ac-D-aIle could be obtained from an Ac-L-Ile-excess mixture by recystallization from water. 相似文献
14.
《Nucleosides, nucleotides & nucleic acids》2013,32(5-8):611-615
Abstract Both D- and L-2′-fluoro-4′-thio-2′,3′-unsaturated nucleosides were synthesized and their anti-HIV activity against the drug sensitive virus and lamivudine-resistant mutant (M184V) were evaluated. In vitro antiviral evaluation indicated that the L-isomers are more potent than the D-isomers, but unfortunately all were cross-resistant with 3TC. Molecular modeling studies revealed that the unnatural sugar moiety of the L-nucleosides as well as 4′-sulfur atom of the D-isomer has a steric conflict with the bulky side chain of valine 184, resulting in cross-resistance. 相似文献
15.
Haruo Tanaka Tadatoshi Hayashi Kiyoshi Nakayama 《Bioscience, biotechnology, and biochemistry》2013,77(7):1731-1736
During the investigation for dephosphorylation of 4-hydroxy-1-β-D-ribofuranosylpyrazolo-[3,4-d] pyrimidine 5′-phosphate, it was found that the compound was converted to an unknown substance by alkaline hydrolysis for 3 hr at 140°C. The structure of the substance was assigned to be 5-amino-1-β-D-ribofuranosylpyrazole-4-carboxamide 5′-phosphate. 5(or3)-Amino- pyrazole-4-carboxamide and its riboside were also obtained from 4-hydroxypyrazolo [3,4-d] pyrimidine and its riboside, respectively, under the similar conditions.5-Amino-1-β-D-ribofuranosyipyrazole-4-carboxamide and 5-amino-1-β-D-ribofuranosyl- pyrazole-4-carboxamide 5′-phosphate are new compounds. 相似文献
16.
17.
《Bioscience, biotechnology, and biochemistry》2013,77(8):1374-1375
D-Ins(1,3,4,5)P4 and unnatural L-Ins(1,3,4,5)P4 were prepared in gram-quantities from D- and L-2,6-di-O-benzyl-myo-inositol by a chemical phosphorylation and deprotection step in high yield and purity without extensive purification. The optically pure benzyl derivatives were obtained by enzyme-catalyzed resolution of racemic 2,6-di-O-benzyl-myo-inositol under acyl-transfer conditions in vinyl acetate as the acyl donor. The lipase of Candida antarctica only acetylated regio- and enantio-selectively the L-enantiomer, providing exclusively L-5-acetyl-2,6-di-O-benzyl-myo-inositol, whereas the D-enantiomer remained unchanged. 相似文献
18.
《Bioscience, biotechnology, and biochemistry》2013,77(2):308-312
[13C]Formaldehyde was selectively incorporated into the C-1 position of D-fructose 6-phosphate by condensation with D-ribulose 5-phosphate catalyzed by a partially purified enzyme system for formaldehyde fixation in Methylomonas aminofaciens 77a. Much of the [1-13C]D-fructose 6-phosphate produced in this reaction was converted to [1-13C]D-glucose 6-phosphate by the addition of glucose-6-phosphate isomerase. A fed-batch reaction with periodic additions of the substrates afforded 56.2 g/liter D-glucose 6-phosphate and 26.8g/liter D-fructose 6-phosphate. When [13C]methanol was used as the C1-donor, the yield of [1-13C]D-glucose 6-phosphate was high when alcohol oxidase was added. The optimum conditions for sugar phosphate production in the fed-batch reaction gave 45.6g/liter [1-13C]D-glucose 6-phosphate and 16.4g/liter [1-13C]D-fructose 6-phosphate in 165min. The molar yield of the total sugar phosphates to methanol added was 95%. The addition of H2O2 and catalase to the reaction system supplied molecular oxygen for methanol oxidation to formaldehyde by alcohol oxidase. 相似文献
19.
Susumu Ikegami Yutaka Hirose Yuji Kamiya Saburo Tamura 《Bioscience, biotechnology, and biochemistry》2013,77(13):2453-2457
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. 相似文献
20.
《Bioscience, biotechnology, and biochemistry》2013,77(10):1730-1735
L-Tartrate in wines and grapes was enzymatically quantified by using the secondary activity of D-malate dehydrogenase (D-MDH). NADH formed by the D-MDH reaction was monitored spectrophotometrically. Under the optimal conditions, L-tartrate (a 1.0 mM sample solution) was fully oxidized by D-MDH in 30 min. A linear relationship was obtained between the absorbance difference and the L-tartrate concentration in the range of a 0.02-1.0 mM sample solution with a correlation coefficient of 0.9991. The relative standard deviation from ten measurements was 1.71% at the 1.0 mM sample solution level. The proposed method was compared with HPLC, and the values determined by both methods were in good agreement. 相似文献