Synthesis of chromogenic substrates of α-amylases on a cyclodextrin basis

Farkas, Erzsébet; Jánossy, Lóránt; Harangi, János; Kandra, Lili; Lipták, András

doi:10.1016/s0008-6215(97)00187-0

Cited by 40 publications

(30 citation statements)

References 22 publications

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“…[33] Subsequent per-acetylation with acetic anhydride and per-benzoylation with benzoyl bromide followed by nucleophilic substitution with sodium azide allowed isolation of the compounds 8 and 9, respectively. [34] Several methodologies are reported to form the linear malto-oligosaccharide from the corresponding CDs with Lewis or Brønsted acids such as H 2 SO 4 /Ac 2 O, [35] FeCl 3 / Ac 2 O, [36] ZnBr 2 /PhSSiMe 3 , [37] HClO 4 /Ac 2 O, [38,39] TiCl 4 , or BF 3 /MeOCH 2 CO 2 H. [40] These different protocols were evaluated on the acetylated derivative 8 without any success. The expected linear heptasaccharide was only formed with H 2 SO 4 /Ac 2 O [35] and in a low yield (less than 10 %) due to the formation of shorter linear oligomers by a depolymerization process.…”

Section: Resultsmentioning

confidence: 99%

Clustering of Escherichia coli Type‐1 Fimbrial Adhesins by Using Multimeric Heptyl α‐D‐Mannoside Probes with a Carbohydrate Core

Almant

Moreau

Kovensky

et al. 2011

Chemistry A European J

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Heptyl α-D-mannoside (HM) is a strong inhibitor of the FimH lectin that mediates the initial adhesion of the uropathogenic Escherichia coli (E. coli) to the bladder cells. We designed a set of multivalent HM ligands based on carbohydrate cores with structural valencies that range from 1 to 7. The chemical strategy used to construct the regular hydrophilic structures consisted of the repetition of a critical glucoside fragment. A primary amino group was grafted at the sugar reducing end to couple the multimers to a fluorescent label. A one-pot synthetic approach was developed to tether the ligands and the fluorescein isothiocyanate (FITC) probe to the scaffold simultaneously. Isothermal calorimetry with the monomeric FimH lectin revealed nanomolar affinities and saturation of all structurally available binding sites on the multivalent HM ligands. Direct titrations domain showed almost strict correlation of enthalpy-entropy compensation with increasing valency of the ligand, whereas reverse titration calorimetry demonstrated negative cooperativity between the first and the second binding site of the divalent heptyl mannoside. A multivalency effect was nevertheless observed by inhibiting the haemagglutination of type-1 piliated UTI89 E. coli, with a titer as low as 60 nM for the heptavalent HM ligand. An FITC-labeled HM trimer showed capture and cross-linking of living bacteria in solution, a phenomenon not previously described with low-valency ligands.

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Section: Resultsmentioning

confidence: 99%

Clustering of Escherichia coli Type‐1 Fimbrial Adhesins by Using Multimeric Heptyl α‐D‐Mannoside Probes with a Carbohydrate Core

Almant

Moreau

Kovensky

et al. 2011

Chemistry A European J

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“…CNP‐maltooligosaccharides of longer chain length, in the range of DP 8–11, were obtained by a transglycosylation reaction catalysed by rabbit skeletal muscle phosphorylase b using α‐ D ‐glucopyranosyl‐phosphate as a donor [25]. The primer in the enzymatic reaction was CNP β‐maltoheptaoside (G 7 ‐CNP), synthesised from β‐cyclodextrin using a convenient chemical method [24]. These maltooligomer substrates are indispensable tools in the investigation of binding sites and the actions of α‐amylases having a longer binding area than that of human α‐amylases.…”

Section: Resultsmentioning

confidence: 99%

“…The homologous maltooligomer substrate series 1, 2 (Fig. 1) (DP 4–8) were synthesised from cyclodextrins [24]. The longer chain length of CNP‐maltooligosides in the range of DP 8–10 was prepared by a chemoenzymatic procedure using rabbit skeletal muscle glycogen phosphorylase b [25].…”

Section: Methodsmentioning

confidence: 99%

Action pattern and subsite mapping of Bacillus licheniformis α‐amylase (BLA) with modified maltooligosaccharide substrates

et al. 2002

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This study represents the first characterisation of the substrate-binding site of Bacillus licheniformis K K-amylase (BLA). It describes the first subsite map, namely, number of subsites, apparent subsite energies and the dual product specificity of BLA. The product pattern and cleavage frequencies were determined by high-performance liquid chromatography, utilising a homologous series of chromophore-substituted maltooligosaccharides of degree of polymerisation 4^10 as model substrates. The binding region of BLA is composed of five glycone, three aglycone-binding sites and a 'barrier' subsite.Comparison of the binding energies of subsites, which were calculated with a computer program, shows that BLA has similarity to the closely related Bacillus amyloliquefaciens K Kamylase. ß

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“…GalG 2 CNP was purchased from SORACHIM SA (Lausanne, Switzerland). CNP-b-maltooligomer glycosides ( Figure 1) were synthesised from cyclodextrins according to a method published earlier 29 . Acarbose was extracted with water from Glucobay Õ tablet (Bayer, Leverkusen, Germany) and used after freeze-drying.…”

Section: Methodsmentioning

confidence: 99%

Simple ITC method for activity and inhibition studies on human salivary α-amylase

Lehoczki

Szabó

Takács

et al. 2016

Journal of Enzyme Inhibition and Medicinal Chemistry

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Isothermal titration calorimetry (ITC) has an increasing significance in enzyme kinetic studies owing to its general applicability and sensitivity. In the present work, we aimed at developing a simple ITC-based screening procedure for the measurement of human salivary a-amylase (HSA) activity. Reaction of two substrates was studied with three independent methods (ITC, HPLC and spectrophotometry). ITC experiments were made using free and chromophore-containing maltooligomers of different length as substrates. Detailed studies revealed that maltoheptaose or longer oligomers could model properly starch and the presence of aromatic chromophore group did not affect the K M values considerably. It is the first time, when ITC was used to investigate of HSA-catalysed hydrolysis of different substrates (2-chloro-4-nitrophenyl-4-O-a-Dgalactopyranosyl-maltoside, maltoheptaose and starch) in the presence of acarbose inhibitor. All measured IC 50 values are in micromolar range (0.9, 18.6 and 29.0 mM, respectively) and increased in parallel with the degree of polymerisation of substrates.

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Synthesis of chromogenic substrates of α-amylases on a cyclodextrin basis

Cited by 40 publications

References 22 publications

Clustering of Escherichia coli Type‐1 Fimbrial Adhesins by Using Multimeric Heptyl α‐D‐Mannoside Probes with a Carbohydrate Core

Clustering of Escherichia coli Type‐1 Fimbrial Adhesins by Using Multimeric Heptyl α‐D‐Mannoside Probes with a Carbohydrate Core

Action pattern and subsite mapping of Bacillus licheniformis α‐amylase (BLA) with modified maltooligosaccharide substrates

Simple ITC method for activity and inhibition studies on human salivary α-amylase

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