- Supercritical water treatment for cello-oligosaccharide production from microcrystalline cellulose
-
Microcrystalline cellulose was treated in supercritical water at 380 °C and at a pressure of 250 bar for 0.2, 0.4, and 0.6 s. The yield of the ambient-water-insoluble precipitate and its average molar mass decreased with an extended treatment time. The highest yield of 42 wt % for DP2-9 cello-oligosaccharides was achieved after the 0.4 s treatment. The reaction products included also 11 wt % ambient-water-insoluble precipitate with a DPw of 16, and 6.1 wt % monomeric sugars, and 37 wt % unidentified degradation products. Oligo- and monosaccharide-derived dehydration and retro-aldol fragmentation products were analyzed via a combination of HPAEC-PAD-MS, ESI-MS/MS, and GC-MS techniques. The total amount of degradation products increased with treatment time, and fragmented (glucosyln-erythrose, glucosyln-glycolaldehyde), and dehydrated (glucosyln-levoglucosan) were identified as the main oligomeric degradation products from the cello-oligosaccharides.
- Tolonen, Lasse K.,Juvonen, Minna,Niemel?, Klaus,Mikkelson, Atte,Tenkanen, Maija,Sixta, Herbert
-
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- Characterization and mechanism of action of Microbacterium imperiale glucan 1,4-α-maltotriohydrolase
-
In this study, glucan 1,4-α-maltotriohydrolase (AMTS) from Microbacterium imperiale was purified and characterized. Hydrolysis by AMTS was affected by starch structure (e.g., amylose versus amylopectin) and hydrolysis time. During the initial phase of hydrolysis of maltooligosaccharides (G4-G7), AMTS displayed a unique transfer specificity to the transfer of maltotriosyl units. After extensive hydrolysis, maltotriose became the major end product, followed by glucose and maltose. Maltotetraose (G4) was the smallest donor in transglycosylation reactions by AMTS. This is the first study that reports transglycosylation activity of AMTS on maltooligosaccharides. The results of this study suggest that high purity maltotriose can be produced by the hydrolytic action of AMTS on starch.
- Wu, Chunsen,Zhou, Xing,Xu, Yan,Li, Hongyan,Tian, Yaoqi,Xu, Xueming,Jin, Zhengyu
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- Hydrolysis of konjac glucomannan by Trichoderma reesei mannanase and endoglucanases Cel7B and Cel5A for the production of glucomannooligosaccharides
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In this paper we describe the enzymatic hydrolysis of konjac glucomannan for the production of glucomannooligosaccharides using purified Trichoderma reesei mannanase, endoglucanases EGI (Tr Cel7b) and EGII (Tr Cel5a). Hydrolysis with each of the three enzymes produced a different pattern of oligosaccharides. Mannanase was the most selective of the three enzymes in the hydrolysis of konjac mannan and over 99% of the formed oligosaccharides had mannose as their reducing end pyranosyl unit. Tr Cel5A hydrolysate shared similarities with mannanase and Tr Cel7B hydrolysates and the enzyme had the lowest substrate specificity of the studied enzymes. The hydrolysate of Tr Cel7B contained a series of oligosaccharides with non-reducing end mannose (M) and reducing end glucose (G) (MG, MMG, MMMG, and MMMMG). These oligosaccharides were isolated from the hydrolysate by size exclusion chromatography in relatively high purity (86-95%) and total yield (23% of substrate). The isolated oligosaccharides were characterized using acid hydrolysis and HPAEC-PAD (carbohydrate composition), HPLC-RI and HPAEC-MS (to determine the DP of purified oligosaccharides), enzymatic hydrolysis (determination of non-reducing end carbohydrate) and NMR (both 1D and 2D, to verify structure and purity of purified compounds). Hydrolysis of konjac mannan with a specific enzyme, such as T. reesei Cel7B or mannanase, followed by fractionation with SEC offers the possibility to produce glucomannooligosaccharides with defined structure. The isolated oligosaccharides can be utilised as analytical standards, for determination of bioactivity of oligosaccharides with defined structure or as substrates for defining substrate specificity of novel carbohydrate hydrolyzing enzymes.
- Mikkelson, Atte,Maaheimo, Hannu,Hakala, Terhi K.
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- GLYCOSIDE COMPOUND
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Compounds of formula (I″) wherein: R11, R12, R13, R14 and R15 are hydrogen, hydroxyl, C1-6 alkyl, C1-6 alkoxy, C1-6 alkyl-carbonyloxy, or a G-O— group, and at least one of R11, R12, R13, R14 and R15 is a G-O— group, wherein G is a saccharide residue,X1 is a single bond, or a methylene group, an ethylene group, a trimethylene group, a vinylene group or —CH═CH—CH2—,X2 is —CO—O— or —O—CO—,p and q are integer ofs 0 to 7, and p+q=0 to 8,Y1 is methylene, ethylene or an alkenylene group having a carbon number of 2 to 15 and 1 to 3 double bonds, andR16 and R17 are hydrogen, methyl or ethyl, or R16 and R17 form a C3-6 cycloalkyl group, are useful as GLP-1 secretion promoting agents.
- -
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Paragraph 0319; 0320; 0383; 0384
(2013/11/06)
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- Structural and biochemical analyses of glycoside hydrolase families 5 and 26 β-(1,4)-mannanases from Podospora anserina reveal differences upon manno-oligosaccharide catalysis
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The microbial deconstruction of the plant cell wall is a key biological process that is of increasing importance with the development of a sustainable biofuel industry. The glycoside hydrolase families GH5 (PaMan5A) and GH26 (PaMan26A) endo-β-1,4-mannanases from the coprophilic ascomycete Podospora anserina contribute to the enzymatic degradation of lignocellulosic biomass. In this study, P. anserina mannanases were further subjected to detailed comparative analysis of their substrate specificities, active site organization, and transglycosylation capacity. Although PaMan5A displays a classical mode of action, PaMan26A revealed an atypical hydrolysis pattern with the release of mannotetraose and mannose from mannopentaose resulting from a predominant binding mode involving the -4 subsite. The crystal structures of PaMan5A and PaMan26A were solved at 1.4 and 2.85 A resolution, respectively. Analysis of the PaMan26A structure supported strong interaction with substrate at the -4 subsite mediated by two aromatic residues Trp-244 and Trp-245. The PaMan26A structure appended to its family 35 carbohydrate binding module revealed a short and proline-rich rigid linker that anchored together the catalytic and the binding modules.
- Couturier, Marie,Roussel, Alain,Rosengren, Anna,Leone, Philippe,Stalbrand, Henrik,Berrin, Jean-Guy
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p. 14624 - 14635
(2013/07/28)
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- The kinetics of p-nitrophenyl-β-d-cellobioside hydrolysis and transglycosylation by Thermobifida fusca Cel5Acd
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The hydrolysis of p-nitrophenyl-β-1,4-cellobioside (pNP-G2) by the catalytic domain of the retaining-family 5-2 endocellulase Cel5A from Thermobifida fusca (Cel5Acd) was studied. The dominant reaction pathway involves hydrolysis of the aglyconic bond, producing cellobiose (G2) and a 'reporter' species p-nitrophenol (pNP), which was monitored spectrophotometrically to track the reaction. We also detected the production of cellotriose (G3) and p-nitrophenyl-glucoside (pNP-G1), confirming the presence of a competing transglycosylation pathway. We use a mechanistic model of hydrolysis and transglycosylation to derive an expression for the rate of pNP-formation as a function of enzyme concentration, substrate concentration, and several lumped kinetics parameters. The derivation assumes that the quasi-steady-state assumption (QSSA) applies for three intermediate species in the mechanism; we determine conditions under which this assumption is rigorously justified. We integrate the rate expression and compare its integral form to pNP-versus-time data collected for a range of enzyme and substrate concentrations. The integral comparison gives a stringent test of the mechanistic model, and it serves to quantify the lumped kinetics parameters with good statistical precision, particularly a previously unidentified parameter that determines the selectivity of hydrolysis versus transglycosylation. The integrated rate expression accounts well for pNP-versus-time data under all circumstances we have investigated.
- Dingee, John W.,Anton, A. Brad
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scheme or table
p. 2507 - 2515
(2011/01/04)
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- COMBINED USE OF DIPEPTIDYL PEPTIDASE IV INHIBITOR COMPOUND AND SWEETENER
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The present invention provides a novel therapeutic or preventive method, a pharmaceutical composition and use thereof, that exhibit superior anti-obesity effects (body weight-reducing (losing) effects and/or body fat mass-reducing effects). Specifically, the present invention provides a pharmaceutical composition comprising the combination of a dipeptidyl peptidase 4 inhibitor and a sweetener having a GLP-1 secretion-stimulating action, as well as use thereof for the manufacture of a medicament. The present invention also provides a method for treating or preventing obesity, comprising administering an effective amount of (a) a dipeptidyl peptidase 4 inhibitor and (b) a sweetener having a GLP-1 secretion-stimulating action to a patient suffering from symptoms of obesity.
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- Efficient chemoenzymatic oligosaccharide synthesis by reverse phosphorolysis using cellobiose phosphorylase and cellodextrin phosphorylase from Clostridium thermocellum
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Inverting cellobiose phosphorylase (CtCBP) and cellodextrin phosphorylase (CtCDP) from Clostridium thermocellum ATCC27405 of glycoside hydrolase family 94 catalysed reverse phosphorolysis to produce cellobiose and cellodextrins in 57% and 48% yield from α-d-glucose 1-phosphate as donor with glucose and cellobiose as acceptor, respectively. Use of α-d-glucosyl 1-fluoride as donor increased product yields to 98% for CtCBP and 68% for CtCDP. CtCBP showed broad acceptor specificity forming β-glucosyl disaccharides with β-(1→4)- regioselectivity from five monosaccharides as well as branched β-glucosyl trisaccharides with β-(1→4)-regioselectivity from three (1→6)-linked disaccharides. CtCDP showed strict β-(1→4)-regioselectivity and catalysed linear chain extension of the three β-linked glucosyl disaccharides, cellobiose, sophorose, and laminaribiose, whereas 12 tested monosaccharides were not acceptors. Structure analysis by NMR and ESI-MS confirmed two β-glucosyl oligosaccharide product series to represent novel compounds, i.e. β-d-glucopyranosyl-[(1→4)- β-d-glucopyranosyl]n-(1→2)-d-glucopyranose, and β-d-glucopyranosyl-[(1→4)-β-d-glucopyranosyl]n- (1→3)-d-glucopyranose (n = 1-7). Multiple sequence alignment together with a modelled CtCBP structure, obtained using the crystal structure of Cellvibrio gilvus CBP in complex with glucose as a template, indicated differences in the subsite +1 region that elicit the distinct acceptor specificities of CtCBP and CtCDP. Thus Glu636 of CtCBP recognized the C1 hydroxyl of β-glucose at subsite +1, while in CtCDP the presence of Ala800 conferred more space, which allowed accommodation of C1 substituted disaccharide acceptors at the corresponding subsites +1 and +2. Furthermore, CtCBP has a short Glu496-Thr500 loop that permitted the C6 hydroxyl of glucose at subsite +1 to be exposed to solvent, whereas the corresponding longer loop Thr637-Lys648 in CtCDP blocks binding of C6-linked disaccharides as acceptors at subsite +1. High yields in chemoenzymatic synthesis, a novel regioselectivity, and novel oligosaccharides including products of CtCDP catalysed oligosaccharide oligomerisation using α-d-glucosyl 1-fluoride, all together contribute to the formation of an excellent basis for rational engineering of CBP and CDP to produce desired oligosaccharides.
- Nakai, Hiroyuki,Hachem, Maher Abou,Petersen, Bent O.,Westphal, Yvonne,Mannerstedt, Karin,Baumann, Martin J.,Dilokpimol, Adiphol,Schols, Henk A.,Duus, Jens ?.,Svensson, Birte
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experimental part
p. 1818 - 1826
(2011/08/21)
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- Isolation and characterization of a novel thermostable neopullulanase-like enzyme from a hot spring in Thailand
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A gene encoding a thermostable pullulan-hydrolyzing enzyme was isolated from environmental genomic DNA extracted from soil sediments of Bor Khleung hot spring in Thailand. Sequence comparison with related enzymes suggested that the isolated enzyme, designated Env Npu193A, was most likely a neopullulanase-like enzyme. Env Npu193A was expressed in Pichia pastoris as a monomeric recombinant protein. The purified Env Npu193A exhibited pH stability ranging from 3 to 9. More than 60% of enzyme activity was retained after incubation at 60°C for 1 h. Env Npu193A was found to hydrolyze various substrates, including pullulan, starch, and γ-cyclodextrin. The optimal working condition for Env Npu193A was at pH 7 at 75°C with Km and Vmax toward pullulan of 1.22 ± 0.3% and 23.24 ± 1.7 U/mg respectively. Env Npu193A exhibited distinct biochemical characteristics as compared with the previously isolated enzyme from the same source. Thus, a culture-independent approach with sequence-basing was found to be an effective way to discover novel enzymes displaying unique substrate specificity and high thermostability from natural bioresources.
- Tang, Kittapong,Kobayashi, Rutchadaporn Sriprang,Champreda, Verawat,Eurwilaichitr, Lily,Tanapongpipat, Sutipa
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p. 1448 - 1456
(2008/12/20)
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- ACCELERATOR FOR MINERAL ABSORPTION AND USE THEREOF
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The present invention has an object to provide an accelerator for mineral absorption and a composition containing the accelerator. The object is solved by providing an accelerator for mineral absorption comprising cyclic tetrasaccharide and/or saccharide derivatives thereof and a composition containing the accelerator.
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Page/Page column 14
(2008/06/13)
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- Expression, purification, and characterization of the maltooligosyltrehalose trehalohydrolase from the thermophilic archaeon Sulfolobus solfataricus ATCC 35092
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The maltooligosyltrehalose trehalohydrolase (MTHase) mainly cleaves the α-1,4-glucosidic linkage next to the α-1,1-linked terminal disaccharide of maltooligosyltrehalose to produce trehalose and the maltooligosaccharide with lower molecular mass. In this study, the treZ gene encoding MTHase was PCR-cloned from Sulfolobus solfataricus ATCC 35092 and then expressed in Escherichia coli. A high yield of the active wild-type MTHase, 13300 units/g of wet cells, was obtained in the absence of IPTG induction. Wild-type MTHase was purified sequentially using heat treatment, nucleic acid precipitation, and ion-exchange chromatography. The purified wild-type MTHase showed an apparent optimal pH of 5 and an optimal temperature at 85°C. The enzyme was stable at pH values ranging from 3.5 to 11, and the activity was fully retained after a 2-h incubation at 45-85°C. The kcat values of the enzyme for hydrolysis of maltooligosyltrehaloses with degree of polymerization (DP) 4-7 were 193, 1030, 1190, and 1230 s-1, respectively, whereas the kcat values for glucose formation during hydrolysis of DP 4-7 maltooligosaccharides were 5.49, 17.7, 18.2, and 6.01 s-1, respectively. The KM values of the enzyme for hydrolysis of DP 4-7 maltooligosyltrehaloses and those for maltooligosaccharides are similar at the same corresponding DPs. These results suggest that this MTHase could be used to produce trehalose at high temperatures.
- Fang, Tsuei-Yun,Tseng, Wen-Chi,Guo, Meng-Shin,Shih, Tong-Yuan,Hung, Xing-Guang
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p. 7105 - 7112
(2008/02/03)
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- Kinetics of maltooligosaccharide hydrolysis in subcritical water
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The kinetics of the hydrolysis of maltooligosaccharides with a degree of polymerization (DP) of 3-6 in subcritical water was studied using a tubular reactor at temperatures between 200 and 260°C and at a constant pressure of 10 MPa. The maltooligosaccharide disappearance and product formation at residence times shorter than 50 s could be expressed by first-order kinetics. The rate constants for the hydrolysis of each maltooligosaccharide were evaluated. There was a tendency that the exo-site glucosidic bond was hydrolyzed faster than the endo-site one irrespective of the DP of the maltooligosaccharide. The hydrolysis of the maltooligosaccharides was consecutively preceded, and the time dependence of the hydrolysis for maltooligosaccharides with different DPs could be calculated by simultaneously solving the mass balance equations for all the possible saccharides.
- Khajavi, Shabnam Haghighat,Ota, Shuji,Kimura, Yukitaka,Adachi, Shuji
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p. 3663 - 3667
(2007/10/03)
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- Synthesis and characterisation of novel chromogenic substrates for human pancreatic α-amylase
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Derivatives of maltose and maltotriose were chemically synthesised as substrates for human pancreatic α-amylases and subjected to kinetic analysis. Rates measured were shown to reflect both hydrolysis and transglycosylation reactions. 4-O-Methylated derivatives of these substrates underwent only hydrolysis, thereby simplifying kinetic analyses. These modified substrates may be used for the detection and kinetic analysis of α-amylases, and are useful in rapidly screening for novel α-amylase inhibitors and for subsequent kinetic characterisation.
- Damager, Iben,Numao, Shin,Chen, Hongming,Brayer, Gary D.,Withers, Stephen G.
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p. 1727 - 1737
(2007/10/03)
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- Synthesis of trisaccharides and tetrasaccharides by means of intramolecular glycosylation supported by rigid spacers
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Treatment of α,α′-dibromo-m-xylylene with 6-O-unprotected thiomaltoside 4 as glycosyl donor (→ 5), followed by 4-O-unprotected galactoside derivative 6 as acceptor, afforded β-linked macrocyclic trisaccharide 9β in high yield after removal of the 3-O-MPM protective group and subsequent intramolecular glycoside bond formation. Similarly, by the same sequence of steps, the corresponding tetrasaccharide 14β was obtained from 5 and 4b-O-unprotected lactoside 11. For reiterative glycoside bond formation, treatment of α,α′-dibromo-m-xylylene with 3-O-unprotected thioglycoside 15 as donor (→ 16), followed by 4,6-O-unprotected glucoside, and subsequent glycosylation afforded macrocyclic maltotrioside 22, which was transformed into known maltotrioside 23. A sight modification of the protecting-group pattern in maltotrioside synthesis resulted in generally higher yields in the ligation of the building blocks to the m-xylylene spacer, particularly in the second glycosylation step, thus providing macrocyclic maltotrioside 40α, which was transformed into known maltotriosides 41α and 41β.
- Mueller,Schmidt, Richard R.
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p. 2055 - 2066
(2007/10/03)
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- Composition and method for stimulating pollen germination
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Composition for application, in particular to leaves, comprising an excipient, the conventional constituents of compositions for application, in particular to leaves, and an active ingredient, characterized by the fact that the active ingredient is constituted by at least one phytosanitary product capable of stimulating the germination of pollen grains, selected from the group comprising: oligosaccharides having a degree of polymerization up to 10 and comprising up to 10, preferably up to 5 and, even more preferably, two glucidic units linked by β1-3, β1-4 et α1-3, particularly those of the group comprising laminaribiose, cellobiose, nigerose, laminaritriose, laminaritetraose and laminaripentaose, derivatives of the above oligosaccharides substituted on the free anomeric carbon atom or on all the carbon atoms having a free hydroxide by a radical selected from the group comprising: C1to C5alkyl radicals, preferably the methyl radical, C1to C5acyl radicals, preferably the acetyl radical, aryl radicals, preferably pyridylamino radicals, cycloalkyl radicals from Cxto Cy, amines, the N-acetyl radical and sulfate and phosphate radicals.
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-
- Anomer-Selective Glucosylation of l-Menthol by Yeast α-Glucosidase
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l-Menthol was glucosylated by the α-glucosidase (EC 3.2.1.20) of Saccharomyces cerevisiae using maltose as the glucosyl donor. When 50 mg of l-menthol and 1.6 M maltose in 10 mM citrate-phosphate buffer (pH 5.5) were incubated at 45°C, l-menthyl α-D-glucopyranoside (α-MenG) was α-anomer-selectively formed as a product. The specificity of the α-linkage was confirmed by 13C-NMR analysis. In the reaction mixture after 2 h, α-MenG was mainly accumulated in a crystalline form and the concentration of dissolved α-MenG was constant at 1.4 mM. The molar conversion yield of α-MenG produced based on the supplied l-menthol was maximally 30.7% at 48 h of reaction.
- Nakagawa, Hiroyuki,Yoshiyama, Masaaki,Shimura, Susumu,Kirimura, Kohtaro,Usami, Shoji
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p. 1332 - 1336
(2007/10/03)
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- Study of the action of human salivary alpha-amylase on 2-chloro-4-nitrophenyl α-maltotrioside in the presence of potassium thiocyanate
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The degradation mechanism of a synthetic substrate, 2-chloro-4-nitrophenyl α-maltotrioside (CNP-G3), by human salivary alpha-amylase (HSA) was investigated by kinetic and product analyses. It was observed that the enzyme attacked the various CNP-maltooligosaccharides (CNP-G3, to CNP-G6) releasing free CNP. Addition of 500 mM potassium thiocyanate (KSCN) was also found to greatly increase the rates of CNP-release. It was the fastest with CNP-G3, and, in the presence of KSCN, was almost comparable to that of degradation of maltopentaose (G5). On the other hand, addition of KSCN decreased the rate of cleavage between glucan-glucan bonds in maltopentaose. Product analysis showed that KSCN addition altered the cleavage distribution which occurred 100% at the bond between CNP and G3, and that product distribution of free CNP was largely dependent on substrate concentration. Formation of CNP-G6, a larger product than the original substrate CNP-G3, was found to be present in the digest at high concentrations of substrate and in the presence of KSCN. Based on these results, a degradation pathway for CNP-G3 involving transglycosylation besides direct hydrolysis is proposed. The increase of the CNP-release by the addition of KSCN would result from a corresponding increase in the interaction between the CNP moiety and the corresponding subsite near the catalytic site, as well as the enhancement of the catalytic efficiency.
- Suganuma, Toshihiko,Maeda, Yoshiaki,Kitahara, Kanefumi,Nagahama, Tomonori
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p. 219 - 227
(2007/10/03)
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- Distinguishable Action between Acid-stable and Neutral α-Amylases from Shochu Koji (Aspergillus kawachii)
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Acid-stable (KAA) and neutral (KNA) α-amylases from shochu koji (A. kawachii) were purified and their actions towards maltooligosaccharides were studied. KAA could be distinguished from KNA by the following actions: with KAA, maltopentaose (G5) was preferentially hydrolyzed at the third glycoside bond, and the addition of potassium thiocyanate (KSCN) decreased the rate of CNP-release from 2-chloro-4-nitrophenyl-α-maltotrioside (CNP-G3).
- Suganuma, Toshihiko,Noda, Naoyuki,Honbo, Hiroyuki,Kitahara, Kanefumi
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p. 1617 - 1619
(2007/10/03)
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- Dehydrative Glycosylation Using Heptabenzyl Derivatives of Glucobioses and Lactose
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Dehydrative glycosylations of the 2-, 3-, 4-, and 6-OH groups of D-glucopyranose with hepta-O-benzyl derivatives of glucobioses (O-D-glucopyranosyl-(1->n)-D-glucopyranose; n = 2, 3, 4, or 6) and lactose, in the presence of a ternary mixture of p-nitrobenzenesulfonyl chloride, silver trifluoromethanesulfonate, and triethylamine in dichloromethane showed that the selectivity of the reaction depended on the anomeric configuration and the linking position to the reducing tribenzylglucose moiety of the nonreducing tetrabenzylglucosyl residue and on the class of the OH group to be glycosylated.The use of a quaternary mixture of p-nitrobenzenesulfonyl chloride, silver trifluoromethanesulfonate, N,N-dimethylacetamide, and triethylamine made all but the β(1->2)-linked biosyl donor undergo α-condensation.Several new linear trisaccharides were obtained via debenzylation of the condensates.
- Koto, Shinkiti,Morishima, Naohiko,Shichi, Sonoko,Haigoh, Hisamitsu,Hirooka, Motoko,et al.
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p. 3257 - 3274
(2007/10/02)
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- Subsite Structure of Chalara paradoxa Glucoamylase and Interaction of the Glucoamylase with Cyclodextrins
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The action of Chalara paradoxa glucoamylase (raw-starch-digesting enzyme) was studied with linear and cyclic maltodextrins.Subsite affinities (Ai) of the amylase were evaluated by the subsite theory.The active site was considered to be made up of seven subsites: A1 = 0.05 kcal/mol, A2 = 4.99 kcal/mol, A3 = 1.30 kcal/mol, A4 = 0.77 kcal/mol, A5 = 0.33 kcal/mol, A6 = 0.21 kcal/mol and A7 = 0.21 kcal/mol.Inhibitions by alpha-, beta-, and gamma-cyclodextrins were competitive for starch digestion by C. paradoxa glucoamylase.The inhibitor constants (Ki) of α-, β-, and γ-cyclodextrin for the amylase were 8.9, 1.4, and 3.9 mM, respectively.The Michaelis constant (Km) of 6-O-α-maltosyl-α-cyclodextrin digestion was 0.79 mM for the amylase.
- Monma, Mitsuru,Yamamoto, Yoshihiro,Kainuma, Keiji
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p. 1503 - 1508
(2007/10/02)
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- ENZYMIC SYNTHESES OF DOUBLY BRANCHED CYCLOMALTOHEPTAOSES THROUGH THE REVERSE ACTION OF Pseudomonas ISOAMYLASE
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Two and three new cyclomaltoheptaose (β-cyclodextrin, cG7) derivatives, respectively, were identified among the products obtained by the action of Pseudomonas isoamylase on maltose and maltotriose, and cG7.They were 6A,6D-di-O-α-maltosyl-cG7 and 6-O-α-(62-O-α-maltosyl)maltosyl-cG7, and 6A,6D-di-O-α-maltotriosyl-cG7, 6-O-α-(63-O-α-maltotriosyl)maltotriosyl-cG7, and 6-O-α-(62-O-α-maltotriosyl)maltotriosyl-cG7.In addition, 61- and 62-O-α-maltosylmaltose were identified as mutual condensation products of maltose.Maltose was the smallest substrate to act as both an acceptor and a donor for the action of Pseudomonas isoamylase.
- Abe, Jun-ichi,Hizukuri, Susumu,Koizumi, Kyoko,Kubota, Yoko,Utamura, Toshiko
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- ELECTROCHEMICAL DETECTION OF REDUCING CARBOHYDRATES PRODUCED BY THE TRANSFERASE ACTION OF YEAST DEBRANCHING ENZYME ON MALTOSACCHARIDES
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A sensitive method for the detection of maltosaccharides up to maltoheptaose is based on an electrochemical detector using bis(1,10-phenanthroline)-copper(II) in the post column reaction after h.p.l.c. on an amino-bonded column.This method has been used for the analysis of the maltosyl and maltotriosyl transferase action of the yeast debranching enzyme with maltosaccharides as the substrates.The smallest donor substrate for maltosyl transfer was maltotetraose, and maltopentaose, maltohexaose, and maltoheptaose were donor substrates for both maltosyl and maltotriosyl transfers.Maltosyl residues were transferred in preference to maltotriosyl residues from maltopentaose, but maltotriosyl residues were transferred prefentially from maltohexaose and maltoheptaose.Maltotriose is an acceptor but not a donor of maltosyl and maltotriosyl transfers.
- Tabata, Shiro,Ide, Takeshi
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p. 245 - 252
(2007/10/02)
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- KINETICS OF ENZYMIC HYDROLYSIS OF MALTO-OLIGOSACCHARIDES: A COMPARISON WITH ACID HYDROLYSIS
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The hydrolysis of malto-oligosaccharides G3-G6 catalysed by porcine pancreatic alpha-amylase was investigated kinetically at 25 deg C.Kinetic parameters corresponding to different positions of enzymic attack were determined and product inhibition was evaluated.The enzymic hydrolysis was compared in terms of reaction rate and pattern of action with hydrolysis in 0.1M H2SO4 at 70 deg C.Mathematical models for the mechanism of hydrolysis were developed and a good rationalisation of the experimental result was achieved.
- Beltrame, Pier Luigi,Carniti, Paolo,Focher, Bonaventura,Marzetti, Annamaria,Santoro, Cataldo,et al.
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- Synthesis of branched cyclomalto-oligosaccharides using Pseudomonas isoamylase.
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Branched cyclomalto-oligosaccharides (cyclodextrins) were synthesised from cyclomalto-oligosaccharides and maltose or maltotriose through the reverse action of Pseudomonas isoamylase. The reaction rate was greater with maltotriose than with maltose, and with increasing size of the cyclomalto-oligosaccharide (cG6 less than cG7 less than cG8). Maltotriose is effective as both a side-chain donor and acceptor, and three isomers of 6-O-alpha-maltotriosylmaltotriose (branched G6) were formed through mutual condensation, but maltose was effective only as a side-chain donor. Each branched cyclomalto-oligosaccharide and G6 was purified by liquid chromatography, and their structures were determined by chemical, enzymic, and 13C-n.m.r. spectroscopic analyses.
- Abe,Mizowaki,Hizukuri,Koizumi,Utamura
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- CHARCTERISATION OF THE OLIGOSACCHARIDES PRODUCED ON HYDROLYSIS OF GALACTOMANNAN WITH β-D-MANNANASE
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Treatment of hot-water-soluble carob galactomannan with β-D-mannanases from A. niger or lucerne seed affords an array of D-galactose-containing β-D-mannosaccharides as well as β-D-manno-biose, -triose, and tetraose (lucerne-seed enzyme only).The D-galactose-containing β-D-mannosaccharides of d.p. 3-9 produced by A. niger β-D-mannanase have been characterised, using enzymic, n.m.r., and chemical techniques, as 61-α-D-galactosyl-β-D-mannobiose, 61-α-D-galactosyl-β-D-mannotriose, 63,64-di-α-D-galactosyl-β-D-mannopentaose (the only heptasaccharide), and 63,64-di-α-D-galactosyl-β-D-mannohexaose, 64,65-di-α-D-galactosyl-β-D-mannohexaose, and 61,63,64-tri-α-D-galactosyl-β-D-mannopentaose (the only octasaccharides).Four nonasaccharides have also been characterised.Penta- and hexa-saccharides were absent.Lucerne-seed β-D-mannanase produced the same branched tri-, tetra- and hepta-saccharides, and also penta- and hexa-saccharides that were characterised as 61-α-D-galactosyl-β-D-mannotetraose, 63-α-D-galactosyl-β-D-mannotetraose, 61,63-di-α-D-galactosyl-β-D-mannotetraose, 63-α-D-galactosyl-β-D-mannopentaose, and 64-α-D-galactosyl-β-D-mannopentaose.None of the oligosaccharides contained a D-galactose stub on the terminal D-mannosyl group nor were they substituted on the second D-mannosyl residue from the reducing terminal.
- McCleary, Barry V.,Nurthen, Elizabeth,Taravel, Francois R.,Joseleau, Jean-Paul
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- POLYSACCHARIDES OF Eremurus. XV. STRUCTURE OF THE GLUCOMANNAN OF Eremurus lactiflorus.
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Ten oligosaccharides have been isolated from the products of the partial hydrolysis of a native acetylated glucomannan obtained from Eremurus lactiflorus O.Fedtsch.Their structures have been studied with the aid of acid hydrolysis before and after reduction with NaBH4, by the GLC method, and also by chromatography with markers.The compositions and sequence of the monomers in tetra- and heptaoligosaccharides have been determined by the 13C NMR method.The glucomannan from the E. lactiflorus differs from the Eremurus glucomanans studied previously by the ratio of monosaccharides, the presence of O-Ac groups, the degree of polymerization, and the presence of a cellobiose unit (Glcp-Glcp) in the polymer chain.The repeating unit consists of 14 hexose residues.
- Dzhumamuratova, A.,Rakhimov, D. A.,Kondratenko, E. S.
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p. 642 - 646
(2007/10/02)
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