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21.
《Bioscience, biotechnology, and biochemistry》2013,77(11):2456-2464
We have established a unique enzymatic approach for obtaining sulfated disaccharides using Bacillus circulans β-D-galactosidase-catalyzed 6-sulfo galactosylation. When 4-methyl umbelliferyl 6-sulfo β-D-galactopyranoside (S6Galβ-4MU) was used as a donor, the enzyme induced transfer of 6-sulfo galactosyl residue to GlcNAc acceptor. As a result, the desired compound 6'-sulfo N-acetyllactosamine (S6Galβ1-4GlcNAc) and its positional isomer 6'-sulfo N-acetylisolactosamine (S6Gal β1-6GlcNAc) were observed by HPAEC-PAD, in 49% total yield based on the donor added, and in a molar ratio of 1:3.5. With a glucose acceptor, the regioselectivity was substantially changed and S6Galβ1-2Glc was mainly produced along with β-(1-1)α,β-(1-3),β-(1-6) isomers in 74% total yield. When methyl α-D-glucopyranoside (Glcα-OMe) was an acceptor, the enzyme also formed mainly S6Galβ1-2Glcα-OMe with its β-(1-6)-linked isomer in 41% total yield based on the donor added. In both cases, it led to the predominant formation of β-(1-2)-linked disaccharides. In contrast, with the corresponding methyl β-D-glucopyranoside (Glcβ-OMe) acceptor, S6Galβ1-3Glcβ-OMe and S6Galβ1-6Glcβ-OMe were formed in a low total yield of 12%. These results indicate that the regioselectivity and efficiency on the β-D-galactosidase-mediated transfer reaction significantly depend on the anomeric configuration in the glucosyl acceptors. 相似文献
22.
Akira Hirota Akinori Suzuki Hiroshi Suzuki Saburo Tamura 《Bioscience, biotechnology, and biochemistry》2013,77(3):643-647
Three metabolites designated Cyl–1, –2 and –3 were isolated as plant growth regulators from culture filtrate of Cylindrocladium scoparium Morgan, a phytopathogenic fungus. Cy1–2 was obtained as pure crystals, and it revealed marked inhibitory activity on the root growth of lettuce seedlings. Cyl–1 showed inhibition on the same organ, while Cyl–3 showed promotion. 相似文献
23.
Cimini D De Rosa M Panariello A Morelli V Schiraldi C 《Journal of industrial microbiology & biotechnology》2008,35(10):1079-1083
The thermoacidophilic archaeon Sulfolobus solfataricus MT4 encodes a maltooligosyltrehalose synthase (MTS), that catalyzes an intramolecular transglycosylation process converting the glycosidic linkages at the reducing end of dextrins from alpha-1,4 into alpha-1,1. In this research the gene encoding MTS was cloned and expressed in Lactococcus lactis NZ9000 using the so-called NICE system. Growth conditions of the recombinant strain were optimized in flask experiments in relation to enzyme production. Batch experiments in 2 L-fermenters were performed on the best identified semidefined medium and 256 U L(-1) of recombinant MTS were produced. Purified recombinant MTS shows its optimal activity at 70 degrees C and pH 5.5, prefers maltoheptaose and maltohexaose as substrates, and demonstrates minimal side hydrolytic activity. 相似文献
24.
Yusuke Mimura Toshihiko Katoh Radka Saldova Roisin O Flaherty Tomonori Izumi Yuka Mimura-Kimura Toshiaki Utsunomiya Yoichi Mizukami Kenji Yamamoto Tsuneo Matsumoto Pauline M. Rudd 《蛋白质与细胞》2018,9(1):47
Glycosylation of the Fc region of IgG has a profound impact on the safety and clinical efficacy of therapeutic antibodies. While the biantennary complex-type oligosaccharide attached to Asn297 of the Fc is essential for antibody effector functions, fucose and outer-arm sugars attached to the core heptasaccharide that generate structural heterogeneity (glycoforms) exhibit unique biological activities. Hence, efficient and quantitative glycan analysis techniques have been increasingly important for the development and quality control of therapeutic antibodies, and glycan profiles of the Fc are recognized as critical quality attributes. In the past decade our understanding of the influence of glycosylation on the structure/function of IgG-Fc has grown rapidly through X-ray crystallographic and nuclear magnetic resonance studies, which provides possibilities for the design of novel antibody therapeutics. Furthermore, the chemoenzymatic glycoengineering approach using endoglycosidase-based glycosynthases may facilitate the development of homogeneous IgG glycoforms with desirable functionality as nextgeneration therapeutic antibodies. Thus, the Fc glycans are fertile ground for the improvement of the safety, functionality, and efficacy of therapeutic IgG antibodies in the era of precision medicine. 相似文献
25.
Se-Wook Jung Tae-Kwon Kim Kwang-Woo Lee Yong-Hyun Lee 《Biotechnology and Bioprocess Engineering》2007,12(3):207-212
The catalytic properties of β-cyclodextrin glucanotransferase (β-CGTase) from alkalophilicBacillus sp. BL-12 specific for the intermolecular transglycosylation of stevioside were investigated. The molecular mass of purified
β-CGTase by ultra-filtration and β-cyclodextrin polymer affinity chromatography was estimated to be 90 kDa, which is high
compared to other known bacterial CGTases. The optimal pH and temperature were 9.0 and 50°C, respectively, and thermal stability
at 40°C was elevated 10-fold in the presence of 1% maltodextrin. The kinetic parameters of the new β-CGTase from alkalophilicBacillus sp. BL-12 indicate that it is more suitable for transglycosylation than the cyclization reaction. Maltodextrin was the most
suitable glycosyl donor for transglycosylation of stevioside. The transglycosylation of stevioside was carried out using 60
units of CGTase per gram of maltodextrin, 20 g/L stevioside as the glycosyl acceptor, and 50 g/L maltodextrin as the gycosyl
donor at 40°C for 6 h, and a conversion yield of stevioside as high as 76% was obtained. 相似文献
26.
《Bioscience, biotechnology, and biochemistry》2013,77(2):344-345
The existence of glycosylated DNA-binding proteins was demonstrated in a whole cell extract from a filamentous fungus, Aspergillus oryzae. The proteins were specifically eluted from a DNA-cellulose column by the eluate containing shared double-stranded DNA and were detected by wheat germ agglutinin (WGA)-probing. The apparent molecular masses of these proteins on SDS-PAGE were 140 kDa, 115 kDa, 105kDa, 68 kDa, and 60 kDa. The labeling of the proteins by uridine 5′-diphosphate(UDP)-[14C]galactose using galactosyltransferase showed the same electrophoretic pattern with the WGA-probing. The [14C]- galactose-labeled saccharides were released from the proteins by mild-base treatment but not by N-glycopeptidase F digestion, indicating the O-glycosidic linkage of the saccharide chain attachment to proteins. The [14C]galactose-labeled saccharides co-migrated with galactose-(β1 → 4)-N-acetylglucosaminitoI on a silica gel plate. Thus, it was seen that several proteins which had the DNA-binding activity were modified by N-acetylglucosamine monosaccharide through an O-glycosidic linkage in A. oryzae. 相似文献
27.
Morifusa Eto Masasumi Sakata Tamotsu Sasayama 《Bioscience, biotechnology, and biochemistry》2013,77(4):645-650
Sixteen phosphate or phosphorothioate esters related to neurotoxic tri-p-ethylphenyl phosphate and its active metabolites were synthesized and their biological activities including inhibitory activity against cholinesterases, insecticidal activity, toxicity to mammals and neurotoxicity were examined. Dialkyl p-ethylphenyl phoshates, p-acetylphenyl phosphates and their thiono analogs showed insecticidal activity, but did not show the ataxic sign by any sublethal doses in hens. When a methyl group was introduced on p-acetylphenyl ring, the biological activity changed remarkably by its position. The introduction of a methyl group into o-position made the ester inactive, while the introduction into m-position made it active to insects selectively. 相似文献
28.
Marie Zarevúcka Miroslav Vacek Zdeněk Wimmer Christine Brunet Marie-Dominique Legoy 《Biotechnology letters》1999,21(9):785-790
2-(4-Methoxybenzyl)-1-cyclohexyl--d-glucopyra nosides (1b and 2b) and 2-(4-methoxybenzyl)-1-cyclohexyl--d-galactopy ranosides (1c and 2c), models for glycosidic juvenogens, were synthesized using either D-glucose or D-galactose [in their natural form (3 and 5) or activated form (4 and 6)], and the respective racemic cis or trans isomers of 2-(4-methoxybenzyl)-1-cyclohexanol (1a and 2a) by either enzymic reverse hydrolysis or transglycosylation under both standard heating and microwave irradiation. Commercially available almond -glucosidase (EC 3.2.1.21) or -galactosidase (EC 3.2.1.23) from Escherichia coli were employed using different acetonitrile/water mixtures [9/1 (v/v) for the reverse hydrolysis, and 4/1 (v/v) for the transglycosylation]. 相似文献
29.
Eneyskaya EV Brumer H Backinowsky LV Ivanen DR Kulminskaya AA Shabalin KA Neustroev KN 《Carbohydrate research》2003,338(4):313-325
A beta-D-xylosidase with molecular mass of 250+/-5 kDa consisting of two identical subunits was purified to homogeneity from a cultural filtrate of Aspergillus sp. The enzyme manifested high transglycosylation activity in transxylosylation with p-nitrophenyl beta-D-xylopyranoside (PNP-X) as substrate, resulting in regio- and stereoselective synthesis of p-nitrophenyl (PNP) beta-(1-->4)-D-xylooligosaccharides with dp 2-7. All transfer products were isolated from the reaction mixtures by HPLC and their structures established by electrospray mass spectrometry and 1H and 13C NMR spectroscopy. The glycosides synthesised, beta-Xyl-1-->(4-beta-Xyl-1-->)(n)4-beta-Xyl-OC6H4NO2-p (n=1-5), were tested as chromogenic substrates for family 10 beta-xylanase from Aspergillus orizae (XynA) and family 11 beta-xylanase I from Trichoderma reesei (XynT) by reversed-phase HPLC and UV-spectroscopy techniques. The action pattern of XynA against the foregoing PNP beta-(1-->4)-D-xylooligosaccharides differed from that of XynT in that the latter released PNP mainly from short PNP xylosides (dp 2-3) while the former liberated PNP from the entire set of substrates synthesised. 相似文献
30.
A -glycosidase of a thermophile, Thermus thermophilus, belonging to the glycoside hydrolase family 1, was cloned and overexpressed in Escherichia coli. The purified enzyme (Ttgly) has a broad substrate specificity towards -D-glucoside, -D-galactoside and -D-fucoside derivatives. The thermostability of Ttgly was exploited to study its kinetic properties within the range 25–80[emsp4 ]°C. Whatever the temperature, except around 60[emsp4 ]°C, the enzyme displayed non-Michaelian kinetic behavior. Ttgly was inhibited by high concentrations of substrate below 60[emsp4 ]°C and was activated by high concentrations of substrate above 60[emsp4 ]°C. The apparent kinetic parameters (k
cat
and K
m
) were calculated at different temperatures. Both k
cat
and K
m
increased with an increase in temperature, but up to 75[emsp4 ]°C the values of k
cat
increased much more rapidly than the values of K
m
. The observed kinetics might be due to a combination of factors including inhibition by excess substrate and stimulation due to transglycosylation reactions. Our results show that the substrate could act not only as a glycosyl donor but also as a glycosyl acceptor. In addition, when the glucose was added to reaction mixtures, inhibition or activation was observed depending on both substrate concentration and temperature. A reaction model is proposed to explain the kinetic behavior of Ttgly. The scheme integrates the inhibition observed at high concentrations of substrate and the activation due to transglycosylation reactions implicating the existence of a transfer subsite. 相似文献