Kohlenhydrate mit Stickstoff oder Schwefel im „Halbacetal”︁‐Ring

Paulsen, Hans

doi:10.1002/ange.19660781002

Cited by 54 publications

(12 citation statements)

References 66 publications

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“…2-Amino-2-deoxy-~-glucose was transported with a significantly lower K, value than 3-amino-3-deoxy-~-glucose, 6-amino-6-deoxy-~-glucose or 1 -amino-1 -deoxy-D-galactose. Amino groups in position 4 or 5 of hexose predominantly form ring closure so that they could not be tested as free amino groups [20]. 5-Amino-5-deoxy-~-glucose (noijirimycin) which therefore had the nitrogen in the ring, shows little affinity for the hexose uptake system.…”

Section: Transport Of Positively Charged Glucose Analoguesmentioning

confidence: 99%

Sugar specificity and sugar-proton interaction for the hexose-proton-symport system of Chlorella

1985

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The substrate specificity of the glucose-proton symport system was studied to gain information about the spatial relationship between the binding sites for glucose and proton. Charged glucose analogues such as amino sugars or sugar acids were not transported by the uptake system, with the exception of 2-amino-2-deoxy-~-glucose. This glucosamine was taken up in the charged form in uniport mechanism, i.e. without symport of proton. This result was interpreted to mean that the proton-binding site of the symport system is close to the hydroxyl at carbon 2 of glucose.This interpretation was strengthened by the following facts: The steric position of hydroxyl groups at carbons 1, 2 or 3 of glucose were especially important for efficient transport. 0-Methylation was not tolerated at carbon 1, but it was tolerated at carbons 3,4 or 6.The stoichiometric flow of proton and sugar could be disturbed by removal of hydroxyl group at carbon 1 of glucose. The pH-dependence of sugar transport is sugar-specific, e.g. the amino group at carbon 2 of glucose improves transport at higher pH. The configuration at carbon 2 of glucose influences the specificity for the symported ion.It is concluded that the coupled flow of proton and glucose occurs by simultaneous coordinate movement of both in a transmembrane channel.Incubation of the green alga Chlorella vulgaris with glucose induces a hexose transport system which could be identified as a proton symport system [l, 21. A similar mechanism of transport energization works for nonelectrolyte transport in bacteria, fungi, higher plants and, with Na' instead of H', in animals [3 -61. The basic principles of substrate translocation might therefore be similar. In the past, studies were mostly concerned with the role of protonmotive force in driving nonelectrolyte accumulation. For Chlorella it was found that lack of protons (i.e. alkaline pH-value) drastically increases the K, value for hexose transport [7], while decrease of the membrane potential reduces the affinity of proton for hexose symport [7, 81. A schematic model has been devised where it was postulated that the transport protein has a gated pore with the binding site half-way through the membrane [9]. In this context it became interesting to elaborate the relative place and the structure of the binding site for hexose and for proton. There had been studies with Chlorella, which showed that no single hydroxyl group of the glucose molecule is essential for transport [lo, 111. Long before, careful studies of sugar specificity had been performed with red blood cells, small intestine and yeast [12-151. But all these studies have dealt with the sugar specificity per se and not with the relationship between binding of sugar and proton. The experimental approach for this report was to compare the specificity of the uptake system towards charged and uncharged substrates. The clarification of the interaction of sugar and proton binding could help to decide about several important points on the mechanism of transport such as: (a) is proton...

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Section: Transport Of Positively Charged Glucose Analoguesmentioning

confidence: 99%

Sugar specificity and sugar-proton interaction for the hexose-proton-symport system of Chlorella

1985

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“…De-O-isopropylidenation of 3 and 5 by 60% acetic acid and subsequent acetylation at O°C respectively gave 2-acetamido-1,4,6-tri-0-acetyl-2,3-dideoxy-ex-and -{3-D-arabino-hexopyranoses (7a, 7b), and 2-acetamido-1,4,6-tri-0-acetyl-2,3-dideoxy-ex-D-ribo-hexopyranose (8), which was identical with the acetylated Lividosamine. amido-2-deoxy-5,6-0-isopropylidene-D-glucofuranose (13) has been described previously. 5 ) 2-Acetamido-2-deoxy-5,6-0-isopropylidene-3-0-methyl-and -3-0-(tetrahydropyran-2-yl)-D-glucofuranoses (14,15) were synthesized from benzyl 2-acetamido-2-deoxy-5,6-0-isopropylidene-{3-D-glucofuranoside 3 ) (9), via 3-0-methyl and 3-0-(tetrahydropyran-2-yl) compounds, respectively.…”

Section: Resultsmentioning

confidence: 99%

“…5 ) 2-Acetamido-2-deoxy-5,6-0-isopropylidene-3-0-methyl-and -3-0-(tetrahydropyran-2-yl)-D-glucofuranoses (14,15) were synthesized from benzyl 2-acetamido-2-deoxy-5,6-0-isopropylidene-{3-D-glucofuranoside 3 ) (9), via 3-0-methyl and 3-0-(tetrahydropyran-2-yl) compounds, respectively. For the preparation of 2-aceta~id~-2-deoxy 5,6-0-isopropylidene-D-allofuranose (18), compound 9.was first 3-0-methanesulfonylated with methanesulfonyl chloride to give compound 12, which was then converted by treatment with potassium acetate-aqueous 90% ethanol into benzy12-acetamido-2-deoxy- In order to examine behaviors of 2-acetamido-2-deoxy-furanoses in the presence of an alkaline ion-exchange resin, we prepared 9 kinds of fu'ranoses (3,5,13 20) or benzyl 2,3,5-triacetamido-2,3,5-trideoxy-fJ-D-ribofuranoside (21). in a neutral condition, with subsequent acetylation afforded only the corresponding furanose derivatives.…”

Section: Resultsmentioning

confidence: 99%

The Behavior of Some 2-Acetamido-2-deoxy-furanoses in the Presence of Alkaline Ion-exchange Resin

Okumura¹,

Kiso²,

Hasegawa³

1983

Agricultural and Biological Chemistry

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“…8) In this mechanism, when the glycosidic bond is cleaved, a glycosyl oxocarbonium ion intermediate is formed for catalysis. Evidence of the role of the transition state intermediates came from inhibition studies involving validamine, 9) N substituted valiolamine derivatives, 10) acarbose, 11) nojirimycin, 12) 1 deoxy nojirimycin 13) and N substituted derivatives of 1 deoxynojirimycin. 14) These inhibitors have been designed, synthesized and purified from plant extracts or the culture broth of microorganisms as the analogues of the charge and or the shape of the oxocarbonium ion like transition state intermediates.…”

mentioning

confidence: 99%

“…The operating temperature of the former column was at 40 C and that of the latter was at 65 C, and the flow rate was 1.0 and 0.6 mL min, respectively. 13 C and 1 H NMR spectra were obtained with a JEOL JNM EX 270 spectrometer operating at 68 MHz in the pulsed fourier transform mode with complete proton decoupling, and 270 MHz, respectively. Chemical shifts are expressed in ppm relative to sodium 3 (trimethylsilyl) propanesulfonate sodium salt (TPS) as an internal standard.…”

mentioning

confidence: 99%

Enzymatic Syntheses of Cycloalkyl .BETA.-D-Glucopyranosides and Their Inhibition Activity for Plant .BETA.-Glucosidase

高田¹,

小川²

2004

J. Appl. Glycosci.

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Various models have been proposed for the reaction mechanism of glycosylase in the transition state, 1 4) but a reasonable model remains to be established. The oxocarbonium ion model has been applied to interpret the reaction mechanism of many glycosylases such as lysozyme, 5,6) glucoamylase 7) and glucosidase. 8) In this mechanism, when the glycosidic bond is cleaved, a glycosyl oxocarbonium ion intermediate is formed for catalysis. Evidence of the role of the transition state intermediates came from inhibition studies involving validamine, 9) N substituted valiolamine derivatives, 10) acarbose, 11) nojirimycin, 12) 1 deoxy nojirimycin 13) and N substituted derivatives of 1 deoxynojirimycin. 14) These inhibitors have been designed, synthesized and purified from plant extracts or the culture broth of microorganisms as the analogues of the charge and or the shape of the oxocarbonium ion like transition state intermediates. 15) They have an easily pro-tonated basic nitrogen atom in the position of the anomeric oxygen or the ring oxygen atom. However, the incorporation of a nitrogen positive center into a pyranose ring requires a relatively long reaction sequence. 16) As its structural similarity with the oxocarbonium ion like transition state intermediates, many researchers have performed their inhibition studies on glycosylases using glucono 1,5 lactone. 17 19) This compound is a relatively strong inhibitor toward glucosidases and has no nitrogen atom in a pyranose ring. However, it has been pointed out that their tendency to undergo hydrolytic ring opening under mildly basic conditions and the conversion into glucono 1,4 lactone (inactive) are the great disadvantage of the measurement of inhibition constants. 18,19) We therefore attempted to prepare more convenient glucosidase inhibitors by enzymatic method, which have rather simple chemical structures without a nitrogen atom in the position of the anomeric oxygen or the ring oxygen atom, and are quite stable in an aqueous solution. MATERIALS AND METHODSMaterials. Cyclopropanemethanol (CPAM) was purchased from Kanto Kagaku Co., Ltd. (Japan). Cyclopentanol (CPE) and cyclopentanemethanol (CPEM) were obtained from Lancaster Co., Ltd. (England). p Nitorophenyl glucopyranoside (pNP G) was a product of Nihon Shokuhin Kako Co., Ltd. (Tokyo). The highly purified glucosidases from Aspergillus niger and Trichoderma viride were generous gifts from Dr. T. Unno, Nihon Shokuhin Kako Co., Ltd. (Japan) and Dr. G. Okada, Shizuoka University (Japan), respectively. The purified sweet almond glucosidase was purchased from Sigma Aldrich (USA). These purified glucosidases were used for the inhibitory studies. On the other hand, glucosidases from Trichoderma reesei (Cellcrust) and A. niger (Novozyme 188) were obtained from Novo Nordisk A S, and the enzymes from T. viride (Meicelase) and sweet almond (BGH 101) were purchased from Meiji Seika Kaisha, Ltd. (Japan) and Toyobo Co., Ltd. (Japan), respectively. These enzymes were used for the preparation of cycloalkyl D J. Appl. Glycosci., 5...

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Kohlenhydrate mit Stickstoff oder Schwefel im „Halbacetal”︁‐Ring

Abstract: Bei 5-

Cited by 54 publications

References 66 publications

Sugar specificity and sugar-proton interaction for the hexose-proton-symport system of Chlorella

Sugar specificity and sugar-proton interaction for the hexose-proton-symport system of Chlorella

The Behavior of Some 2-Acetamido-2-deoxy-furanoses in the Presence of Alkaline Ion-exchange Resin

Enzymatic Syntheses of Cycloalkyl .BETA.-D-Glucopyranosides and Their Inhibition Activity for Plant .BETA.-Glucosidase

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