scholarly journals Inhibition of α-l-fucosidase by derivatives of deoxyfuconojirimycin and deoxymannojirimycin

1990 ◽  
Vol 265 (1) ◽  
pp. 277-282 ◽  
Author(s):  
B Winchester ◽  
C Barker ◽  
S Baines ◽  
G S Jacob ◽  
S K Namgoong ◽  
...  
Keyword(s):  
Carbon Atom ◽  
Human Liver ◽  
Potent Inhibitor ◽  
Competitive Inhibitor ◽  
Piperidine Ring ◽  
Structural Requirement ◽  
Ph Dependency ◽  
Structural Analogues ◽  
Hydroxy Groups ◽  
Derivatives Of

Deoxyfuconojirimycin (1,5-dideoxy-1,5-imino-L-fucitol) is a potent, specific and competitive inhibitor (Ki 1 x 10(-8) M) of human liver alpha-L-fucosidase (EC 3.2.1.51). Six structural analogues of this compound were synthesized and tested for their ability to inhibit alpha-L-fucosidase and other human liver glycosidases. It is concluded that the minimum structural requirement for inhibition of alpha-L-fucosidase is the correct configuration of the hydroxy groups at the piperidine ring carbon atoms 2, 3 and 4. Different substituents in either configuration at carbon atom 1 (i.e. 1 alpha- and beta-homofuconojirimycins) and at carbon atom 5 may alter the potency but do not destroy the inhibition of alpha-L-fucosidase. The pH-dependency of the inhibition by these amino sugars suggests very strongly that inhibition results from the formation of an ion-pair between the protonated inhibitor and a carboxylate group in the active site of the enzyme. Deoxymannojirimycin (1,5-dideoxy-1,5-imino-D-mannitol) is also a more potent inhibitor of alpha-L-fucosidase than of alpha-D-mannosidase. This can be explained by viewing deoxymannojirimycin as beta-L-homofuconojirimycin lacking the 5-methyl group. Conversely, beta-L-homo analogues of fuconojirimycin can also be regarded as derivatives of deoxymannojirimycin. This has permitted deductions to be made about the structural requirements of inhibitors of alpha- and beta-D-mannosidases.

scholarly journals The structural basis of the inhibition of human glycosidases by castanospermine analogues

1990 ◽  
Vol 269 (1) ◽  
pp. 227-231 ◽  
Author(s):  
B G Winchester ◽  
I Cenci di Bello ◽  
A C Richardson ◽  
R J Nash ◽  
L E Fellows ◽  
...  
Keyword(s):  
Structural Feature ◽  
Human Liver ◽  
Potent Inhibitor ◽  
Structural Basis ◽  
Preferential Recognition ◽  
Derivatives Of ◽  
Do So

A series of epimers and deoxy derivatives of castanospermine has been synthesized to investigate the contribution of the different chiral centres to the specificity and potency of inhibition of human liver glycosidases. Castanospermine inhibits all forms of alpha- and beta-D-glucosidases, but alteration to any of the five chiral centres in castanospermine markedly decreases the inhibition. 6-Epicastanospermine, which is related to D-pyranomannose in the same way as castanospermine is to D-pyranoglucose, does not inhibit lysosomal (acidic) alpha-mannosidase, but is a good inhibitor of the cytosolic or neutral alpha-mannosidase. Conversely, 1-deoxy-6-epicastanospermine inhibits acidic alpha-mannosidase strongly, but not the neutral alpha-mannosidase. An explanation of this different inhibition based on preferential recognition of different configurations of mannose by the different forms of alpha-mannosidase is postulated. All derivatives of 6-epicastanospermine also have the minimum structural feature for the inhibition of alpha-L-fucosidase, but those with a beta-anomeric substituent do not inhibit the enzyme, or do so very weakly. 1-Deoxy-6,8a-diepicastanospermine, which has four chiral centres identical with alpha-L-fucose, is, however, a potent inhibitor of alpha-L-fucosidase (Ki 1.3 microM).

scholarly journals Synthesis of nonracemic hydroxyglutamic acids

2019 ◽  
Vol 15 ◽  
pp. 236-255
Author(s):  
Dorota G Piotrowska ◽  
Iwona E Głowacka ◽  
Andrzej E Wróblewski ◽  
Liwia Lubowiecka
Keyword(s):  
Natural Products ◽  
Carbon Atom ◽  
Hydrogen Bonds ◽  
Glutamic Acid ◽  
Functional Groups ◽  
Review Article ◽  
Cellular Processes ◽  
Structural Analogues ◽  
Derivatives Of ◽  
Additional Hydrogen

Glutamic acid is involved in several cellular processes though its role as the neurotransmitter is best recognized. For detailed studies of interactions with receptors a number of structural analogues of glutamic acid are required to map their active sides. This review article summarizes syntheses of nonracemic hydroxyglutamic acid analogues equipped with functional groups capable for the formation of additional hydrogen bonds, both as donors and acceptors. The majority of synthetic strategies starts from natural products and relies on application of chirons having the required configuration at the carbon atom bonded to nitrogen (e.g., serine, glutamic and pyroglutamic acids, proline and 4-hydroxyproline). Since various hydroxyglutamic acids were identified as components of complex natural products, syntheses of orthogonally protected derivatives of hydroxyglutamic acids are also covered.

Synthesis, Docking Studies into CDK-2 and Anticancer Activity of New Derivatives Based Pyrimidine Scaffold and Their Derived Glycosides

2019 ◽  
Vol 19 (13) ◽  
pp. 1093-1110 ◽  
Author(s):  
Adel A.H. Abdel Rahman ◽  
Ibrahim F. Nassar ◽  
Amira K.F. Shaban ◽  
Dina S. EL-Kady ◽  
Hanem M. Awad ◽  
...  
Keyword(s):  
Anticancer Activity ◽  
Human Liver ◽  
Docking Studies ◽  
Cyclin Dependent Kinase ◽  
Binding Interaction ◽  
Enzyme Active Site ◽  
Human Liver Cancer ◽  
Amino Derivatives ◽  
Activity Behavior ◽  
Derivatives Of

Background & Objective:New diaryl-substituted pyrimidinedione compounds, their thioxo derivatives as well as their bicyclic thiazole compounds were synthesized and characterized.Methods:The glycosylamino derivatives of the synthesized disubstituted derivatives of the pyrimidine scaffold were also prepared via reaction of the N3-amino derivatives with a number of monosaccharides followed by acetylation.Results:The anticancer activity of the synthesized compounds was studied against human liver cancer (HepG2) and RPE-1cell lines. Compounds 2a, 2b, 3a and 12 showed potent activities with IC50 results comparable to that of doxorubicin.Conclusion:Docking investigations into Cyclin-dependent kinase 2 (CDK-2) enzyme, a potential target for cancer medication, were also reported showing the possible binding interaction into the enzyme active site to support their activity behavior.

The role of secondary alcoholic groups of D-galacturonan in its degradation with exo-D-galacturonanase

1980 ◽  
Vol 45 (2) ◽  
pp. 427-434 ◽  
Author(s):  
Kveta Heinrichová ◽  
Rudolf Kohn
Keyword(s):  
Acetyl Derivative ◽  
Competitive Inhibitor ◽  
Hydroxyl Groups ◽  
Pectic Acid ◽  
Substrate Complex ◽  
Enzyme Substrate ◽  
The Individual ◽  
Degradation Degree ◽  
Derivatives Of

The effect of exo-D-galacturonanase from carrot on O-acetyl derivatives of pectic acid of variousacetylation degree was studied. Substitution of hydroxyl groups at C(2) and C(3) of D-galactopyranuronic acid units influences the initial rate of degradation, degree of degradation and its maximum rate, the differences being found also in the time of limit degradations of the individual O-acetyl derivatives. Value of the apparent Michaelis constant increases with increase of substitution and value of Vmax changes. O-Acetyl derivatives act as a competitive inhibitor of degradation of D-galacturonan. The extent of the inhibition effect depends on the degree of substitution. The only product of enzymic reaction is D-galactopyranuronic acid, what indicates that no degradation of the terminal substituted unit of O-acetyl derivative of pectic acid takes place. Substitution of hydroxyl groups influences the affinity of the enzyme towards the modified substrate. The results let us presume that hydroxyl groups at C(2) and C(3) of galacturonic unit of pectic acid are essential for formation of the enzyme-substrate complex.

The Interactions of adenylates with allosteric citrate synthase

1979 ◽  
Vol 57 (5) ◽  
pp. 385-395 ◽  
Author(s):  
Michael M. Talgoy ◽  
Harry W. Duckworth
Keyword(s):  
Coenzyme A ◽  
Citrate Synthase ◽  
Potent Inhibitor ◽  
Sulfhydryl Group ◽  
Fluorescence Technique ◽  
Allosteric Site ◽  
Acetyl Coenzyme A ◽  
Nitrobenzoic Acid ◽  
Adenylic Acid ◽  
Derivatives Of

Evidence is presented that a number of derivatives of adenylic acid may bind to the allosteric NADH binding site of Escherichia coli citrate synthase. This evidence includes the facts that all the adenylates inhibit NADH binding in a competitive manner and that those which have been tested protect an enzyme sulfhydryl group from reaction with 5,5′-dithiobis-(2-nitrobenzoic acid) in the same way that NADH does. However, whereas NADH is a potent inhibitor of citrate synthase, most of the adenylates are activators. The best activator, ADP-ribose, increases the affinity of the enzyme for the substrate, acetyl-CoA, and saturates the enzyme in a sigmoid manner. A fluorescence technique, involving the displacement of 8-anilino-1-naphthalenesulfonate from its complex with citrate synthase, is used to obtain saturation curves for several nucleotides under nonassay conditions. It is found that acetyl-coenzyme A, coenzyme A, and ADP-ribose all bind to the enzyme cooperatively, and that the binding of each becomes tighter in the presence of KCl the activator, and oxaloacetic acid (OAA), the second substrate. Another inhibitor, α-ketoglutarate, can compete with OAA in the absence of KClbut not in its presence. The nature of the allosteric site of citrate synthase, and the modes of action of several activators and inhibitors, are discussed in the light of this evidence.

scholarly journals Affinity chromatography and inhibition of chorismate mutase-prephenate dehydrogenase by derivatives of phenylalanine and tyrosine

1977 ◽  
Vol 165 (1) ◽  
pp. 121-126 ◽  
Author(s):  
G D Smith ◽  
D V Roberts ◽  
A Daday
Keyword(s):  
Affinity Chromatography ◽  
Competitive Inhibitor ◽  
Chorismate Mutase ◽  
Prephenate Dehydrogenase ◽  
Step Procedure ◽  
One Step ◽  
High Degree ◽  
Sepharose 4B ◽  
Derivatives Of

Several derivatives of phenylalanine and tyrosine were prepared and tested for inhibition of chorismate mutase-prephenate dehydrogenase (EC 1.3.1.12) from Escherichia coli K12 (strain JP 232). The best inhibitors were N-toluene-p-sulphonyl-L-phenylalanine, N-benzenesulphonyl-L-phenylalanine and N-benzloxycarbonyl-L-phenylalanine. Consequently two compounds, N-toluene-sulphonyl-L-p-aminophenylalanine and N-p-aminobenzenesulphonyl-L-phenylalanine, were synthesized for coupling to CNBr-activated Sepharose-4B. The N-toluene-p-sulphonyl-L-p-aminophenylalanine-Sepharose-4B conjugate was shown to bind the enzyme very strongly at pH 7.5. The enzyme was not eluted by various eluents, including 1 M-NaCl, but could be quantitatively recovered by washing with buffer of pH9. Elution was more effective in the presence of 10 mM-1-adamantaneacetic acid, a competitive inhibitor of the enzyme. This affinity-chromatography procedure results in a high degree of purification of the enzyme and can be used to prepare the enzyme in a one-step procedure from the bacterial crude extract. Such a procedure may therefore prove useful in studying this enzyme in a state that closely resembles that in vivo.

13C-NMR study of the inhibition of δ-chymotrypsin by a tripeptide-glyoxal inhibitor

2002 ◽  
Vol 362 (2) ◽  
pp. 339-347 ◽  
Author(s):  
Aleksandra DJURDJEVIC-PAHL ◽  
Chandralal HEWAGE ◽  
J. Paul G. MALTHOUSE
Keyword(s):  
13C Nmr ◽  
Exchange Process ◽  
Competitive Inhibitor ◽  
Minor Role ◽  
Oxyanion Hole ◽  
Inhibitor Complex ◽  
Rapid Exchange ◽  
Nmr Study ◽  
A Minor ◽  
Hydroxy Groups

A new inhibitor, Z-Ala-Pro-Phe-glyoxal (where Z is benzyloxycarbonyl),has been synthesized and shown to be a competitive inhibitor of δ-chymotrypsin, with a Ki of 25±8nM at pH7.0 and 25°C. Z-Ala-Pro-[1-13C]Phe-glyoxal and Z-Ala-Pro-[2-13C]Phe-glyoxal have been synthesized, and 13C-NMR has been used to determine how they interact with δ-chymotrypsin. Using Z-Ala-Pro-[2-13C]Phe-glyoxal we have detected a signal at 100.7p.p.m. which we assign to the tetrahedral adduct formed between the hydroxy group of Ser-195 and the 13C-enriched keto-carbon of the inhibitor. This signal is in a pH-dependent slow exchange with a signal at 107.6p.p.m. which depends on a pKa of ∼ 4.5, which we assign to oxyanion formation. Thus we are the first to detect an oxyanion pKa in a reversible chymotrypsin—inhibitor complex. A smaller titration shift of 100.7p.p.m. to 103.9p.p.m. with a pKa of ∼ 5.3 is also detected due to a rapid exchange process. This pKa is also detected with the Z-Ala-Pro-[1-13C]Phe-glyoxal inhibitor and gives a larger titration shift of 91.4p.p.m. to 97.3p.p.m., which we assign to the ionization of the hydrated aldehyde hydroxy groups of the enzyme-bound inhibitor. Protonation of the oxyanion in the oxyanion hole decreases the binding efficiency of the inhibitor. From this decrease in binding efficiency we estimate that oxyanion binding in the oxyanion hole reduces the oxyanion pKa by 1.3 pKa units. We calculate that the pKas of the oxyanions of the hemiketal and hydrated aldehyde moieties of the glyoxal inhibitor are both lowered by 6.4–6.9 pKa units on binding to chymotrypsin. Therefore we conclude that oxyanion binding in the oxyanion hole has only a minor role in decreasing the oxyanion pKa. We also investigate how the inhibitor breaks down at alkaline pH, and how it breaks down at neutral pH in the presence of chymotrypsin.

Threonine metabolism in isolated rat hepatocytes

2001 ◽  
Vol 281 (6) ◽  
pp. E1300-E1307 ◽  
Author(s):  
James D. House ◽  
Beatrice N. Hall ◽  
John T. Brosnan
Keyword(s):  
Potent Inhibitor ◽  
Rat Hepatocytes ◽  
Competitive Inhibitor ◽  
Acid Uptake ◽  
Keto Acid ◽  
Glycine Cleavage System ◽  
Isolated Rat Hepatocytes ◽  
Threonine Dehydratase ◽  
Threonine Dehydrogenase ◽  
Glycine Cleavage

The removal of the 1-carbon of threonine can occur via threonine dehydrogenase or threonine aldolase, this carbon ending up in glycine to be liberated by the mitochondrial glycine cleavage system and producing CO2. Alternatively, in the threonine dehydratase pathway, the 1-carbon ends up in α-ketobutyrate, which is oxidized in the mitochondria to CO2. Rat hepatocytes, incubated in Krebs-Henseleit medium, were incubated with 0.5 mMl-[1-14C]threonine, and14CO2 production was measured. Added glycine (0.3 mM) marginally suppressed threonine oxidation. Cysteamine (0.5 mM), a potent inhibitor of the glycine cleavage system, reduced threonine oxidation to 65% of controls. However, α-cyanocinnamate (0.5 mM), a competitive inhibitor of mitochondrial α-keto acid uptake, reduced threonine oxidation to 35% of controls. These data provided strong evidence that ∼65% of threonine oxidation occurs through the glycine-independent threonine dehydratase pathway. Glucagon (10−7 M) increased threonine oxidation and stimulated threonine uptake by these cells. In summary, the majority of threonine oxidation occurs through the threonine dehydratase pathway in rat hepatocytes, and threonine oxidation is increased by glucagon, which also increases threonine's transport.

scholarly journals Synthesis and crystal structures of two purpurin derivatives: 1,4-dihydroxy-2-propoxyanthraquinone and 2-butoxy-1,4-dihydroxyanthraquinone

2017 ◽  
Vol 73 (11) ◽  
pp. 1687-1691 ◽  
Author(s):  
Eric Bosch ◽  
Emily N. McClain
Keyword(s):  
Carbon Atom ◽  
Hydrogen Bonds ◽  
Sodium Hydride ◽  
Maximum Deviation ◽  
Independent Molecule ◽  
Asymmetric Unit ◽  
Terminal Carbon Atom ◽  
Butyl Group ◽  
Independent Molecules ◽  
Hydroxy Groups

The title compounds were obtained by deprotonation of 1,2,4-trihydroxyanthraquinone (purpurin) using sodium hydride followed by reaction with either 1-bromopropane or 1-bromobutane. 1,4-Dihydroxy-2-propoxyanthraquinone crystallizes as a 1:1 solvate from acetonitrile, C17H14O5·CH3CN. The anthraquinone core of the molecule is essentially planar and both hydroxy groups participate in intramolecular O—H...O (carbonyl) hydrogen bonds. The propyl chain is angled slightly above the plane of the anthraquinone moiety with a maximum deviation of 0.247 (2) Å above the plane for the terminal carbon atom. In contrast, 2-butoxy-1,4-dihydroxyanthraquinone, C18H16O5, crystallizes from nitromethane with two independent molecules in the asymmetric unit. The anthraquinone core of each independent molecule is essentially planar and both hydroxy groups on both molecules participate in intramolecular O—H...O(carbonyl) hydrogen bonds. The butyl chain in one molecule is also angled slightly above the plane of the anthraquinone moiety, with a maximum deviation of 0.833 (5) Å above the plane for the terminal carbon atom. In contrast, the butyl group on the second molecule is twisted out of the plane of the anthraquinone core with a torsion angle of 65.1 (3)°, resulting in a maximum deviation of 1.631 (5) Å above the plane for the terminal carbon atom.

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