scholarly journals Polyoxometalates as artificial nucleases: hydrolytic cleavage of DNA promoted by a highly negatively charged ZrIV-substituted Keggin polyanion

2017 ◽  
Vol 53 (3) ◽  
pp. 617-620 ◽  
Author(s):  
T. K. N. Luong ◽  
I. Govaerts ◽  
J. Robben ◽  
P. Shestakova ◽  
T. N. Parac-Vogt
Keyword(s):  
Hydrolytic Cleavage ◽  
Supercoiled Plasmid ◽  
Artificial Nucleases ◽  
Keggin Polyoxometalate ◽  
Hydrolysis Of

A highly negatively charged ZrIV-substituted Keggin polyoxometalate [{α-PW11O39Zr(μ-OH)(H2O)}2]8− (ZrK 2 : 2) promoted the hydrolysis of phosphoester bonds in the supercoiled plasmid pUC19 DNA under physiological pH and temperature.

scholarly journals Hydrolysis of transferrin promoted by a cerium(IV)-Keggin polyoxometalate

Polyhedron ◽  
2019 ◽  
Vol 170 ◽  
pp. 570-575 ◽  
Author(s):  
Jens Moons ◽  
Laura S. Van Rompuy ◽  
Alvaro Rodriguez ◽  
Shorok A.M. Abdelhameed ◽  
Wouter Simons ◽  
...  
Keyword(s):  
Keggin Polyoxometalate ◽  
Hydrolysis Of

scholarly journals Studies on cell adhesion and recognition. III. The occurrence of α-mannosidase at the fibroblast cell surface, and its possible role in cell recognition

1981 ◽  
Vol 88 (1) ◽  
pp. 149-159 ◽  
Author(s):  
H Rauvala ◽  
S Hakomori
Keyword(s):  
Cell Adhesion ◽  
Cell Surface ◽  
Inhibitory Activity ◽  
Time Course ◽  
Gas Chromatography Mass Spectrometry ◽  
Hydrolytic Cleavage ◽  
Intact Cells ◽  
Cell Monolayers ◽  
Mannose 6 Phosphate ◽  
Hydrolysis Of

The occurrence of α-mannosidase activity at the surface of hamster embryo (NIL) fibroblasts is indicated by the following findings: (a) When NIL cells were incubated on the glass surfaces on which ovalbumin glycopeptides were covalently linked, a rapid release of free mannose from ovalbumin glycopeptides was observed as evidenced by analysis on gas chromatography/mass spectrometry. (b) Cell suspensions as well as intact cell monolayers hydrolyzed rapidly p-nitrophenyl-α-D-mannoside, and the time-course of the hydrolytic cleavage was linear from the moment of mixing of the substrate with the cells. The hydrolysis of the nitrophenyl glycosides of β-D-mannose, α-D-galactose, β-D-galactose, α-L-fucose, β-D-glucose, β-D-N-acetylgalactosamine and β-D-N-acetylglucosamine was negligible or more than ten times lower as compared with the hydolysis of α-D-mannoside. (c) No released or secreted activity of mannosidase could be detected under the conditions used. (d) Studies using known proportions of broken cells in the incubation mixture indicated that more than 90 percent of the mannosidase activity measured was attributable to intact cells and not to broken cells or cell fragments. (e) Hydrolysis of p-nitrophenyl-α-D-mannoside by cell monolayers was inhibited, in the order of decreasing inhibitory activity, by yeast mannan, ovalbumin, α-1,4-L-mannonolactone, α-methylmannoside, and mannose-6-phosphate. High inhibitory activity of the mannan polysaccharide and of ovalbumin favored the presence of the mannosidase activity at the cell surface, as these substrates may not penetrate rapidly into the cells. The following findings indicated that the cell surface mannosidase is mediating the cell adhesion based on the recognition of high-mannose-type glycopeptide: (a) Ovalbumin- coated plastic surfaces strongly promoted attachment and spreading of NIL fibroblasts, whereas the same ovalbumin coat did not promote attachment and spreading of some other cell types (BALB/c 3T3 fibroblasts and freshly prepared rat liver cells). (b) Digestion of ovalbumin with α-mannosidase greatly reduced the adhesion-mediating activity. (c) Cell adhesion to ovalbumin-coated surfaces was strongly inhibited by mannose tetrasaccharides, moderately by α-1,4-L-mannonolactone, and weakly by α- methylmannoside and mannose-6-phosphate. This order of the inhibitory activity for cell attachment is the same as that for the inhibition of mannosidic hydrolysis. The interpretation that the cell surface mannosidase is able to mediate cell adhesion is in agreement with previous studies suggesting that polyvalent glycosidase surfaces can promote cell adhesion to a degree similar to that caused by fibronectin and several lectins by interacting with their cell surface substrate site (the accompanying papers of this series).

Quaternary Heteroarenium Aldoximes as Catalysts for Cleavage of Phosphate Esters

1995 ◽  
Vol 60 (5) ◽  
pp. 883-893 ◽  
Author(s):  
František Hampl ◽  
Jiří Mazáč ◽  
František Liška ◽  
Jiří Šrogl ◽  
Lubomír Kábrt ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Critical Micellar Concentration ◽  
Considerable Effect ◽  
Phosphate Esters ◽  
Hexadecyltrimethylammonium Bromide ◽  
Hydrolytic Cleavage ◽  
Pseudo First Order Reaction ◽  
First Order ◽  
Diphenyl Phosphate ◽  
Hydrolysis Of

1-Methyl- (Ia - Id) and 1-dodecyl-2-, 3- and 4-hydroxyiminomethylpyridinium salts (Ie - Ih), as well as 1-methyl- (IIa) and 1-dodecyl-3-hydroxyiminomethylpyridazinium salts (IIb, IIc), were synthesized as catalysts for hydrolytic cleavage of organophosphates. The activities of the prepared catalysts were evaluated by measuring rate constants of hydrolysis of 4-nitrophenyl diphenyl phosphate (PNPDPP) under conditions of a pseudo-first-order reaction. The observed reactivity of pyridinium aldoximes Ia - Ih towards PNPDPP in neutral or slightly basic aqueous solutions (pH 7.2 and 7.8) depends on the acidity of the hydroxyimino group. The cleavage of PNPDPP is strongly accelerated in solutions of 1-dodecylhydroxyiminomethylpyridinium salts Ie - Ih above their critical micellar concentration (CMC). Considerable effect on the velocity of PNPDPP cleavage was observed when quaternary pyridinium aldoximes Ie - Ih were comicellized with inert cationic tenside hexadecyltrimethylammonium bromide (CTAB). 1-Dodecyl-3-hydroxyiminomethylpyridazinium salts IIb and IIc were unstable in aqueous solutions under the above-mentioned conditions.

scholarly journals DEVELOPMENT OF A METHOD FOR HYDROLYTIC CLEAVAGE OF MOLECULES SAPONINS – DERIVATIVES OF QUILLAJA ACID

2020 ◽  
pp. 149-156
Author(s):  
Natal'ya Vladimirovna Mironenko ◽  
Irina Viktorovna Shkutina ◽  
Tat'yana Aleksandrovna Brezhneva ◽  
Vladimir Fedorovich Selemenev
Keyword(s):  
Heating Time ◽  
Uv Spectrophotometry ◽  
Hydrolytic Cleavage ◽  
Absorption Bands ◽  
Chemical Methods ◽  
Physico Chemical ◽  
Aqueous Solvent ◽  
Calculation Results ◽  
Hydrolysis Of ◽  
Derivatives Of

The possibility of hydrolytic decomposition of glycosides soap tree Qullaja. The conditions for the complete hydrolysis of saponins: a mixture of hydrochloric acid, water, ethanol in a ratio of 4 :7.35 : 6.65, heating time – at least 6 hours. The composition of the carbohydrate part of saponins was established – xylose, glucuronic acid, galactose, arabinose were identified in all hydrolysates. The analysis of the obtained fraction of aglycone – willieboy acid physico-chemical methods. Based on the calculation results of chromatographic characteristics (mobility, number and height of theoretical plates), a system for elution of aglycone of the following composition is recommended: petroleum ether–chloroform–acetone (20 : 20 : 5). By the method of potentiometric titration in a non-aqueous solvent medium, the percentage of aglycone in the selected fractions was determined-88.23%. A comparative study of the aqueous solution of aglycone and saponins by UV spectrophotometry. A decrease in the intensity of absorption bands in the 230, 290 nm region responsible for the absorption of carbonyl structures is shown. Analyzed the IR spectra of saponins and willieboy acid identified bands assigned to the vibrations of functional groups of the aglycone and the carbohydrate residue.

scholarly journals Fabrication of highly active phosphatase-like fluorescent cerium-doped carbon dots for in situ monitoring the hydrolysis of phosphate diesters

RSC Advances ◽  
2020 ◽  
Vol 10 (68) ◽  
pp. 41551-41559
Author(s):  
Jinyan Du ◽  
Shuangqing Qi ◽  
Juan Chen ◽  
Ying Yang ◽  
Tingting Fan ◽  
...  
Keyword(s):  
Carbon Dots ◽  
In Situ Monitoring ◽  
Hydrolytic Cleavage ◽  
Highly Active ◽  
Phosphate Diesters ◽  
Doped Carbon Dots ◽  
Hydrolysis Of

The hydrolytic cleavage of BNPP was catalyzed and monitored by the fluorescent CeCDs.

Di(phosphavinyl) Ethers (2,4-Diphospha-3-oxapentadienes)

2009 ◽  
Vol 64 (1) ◽  
pp. 73-82 ◽  
Author(s):  
Roxana M. Birzoi ◽  
Delia Bugnariu ◽  
Christine Goers ◽  
Rafael Guerrero Gimeno ◽  
Thorsten Gust ◽  
...  
Keyword(s):  
31P Nmr ◽  
Cycloaddition Reaction ◽  
Racemic Mixture ◽  
Formation Mechanisms ◽  
Hydrolytic Cleavage ◽  
State Structure ◽  
Dft Methods ◽  
X Ray ◽  
Hydrolysis Of

Hydrolytic cleavage of the P-chlorophosphaalkenes (RMe2Si)2C=PCl (R = Me: 1a; R = iPr: 1b) in the presence of triethylamine leads to di(phosphavinyl) ethers (2,4-diphospha-3-oxapentadienes) [(RMe2Si)2C=P]2O (2a, 2b) as main products, accompanied by alkylphosphinic acids (RMe2Si)2(H)CP(H)(O)OH (3a, 3b). The hydrolysis of (PhMe2Si)2C=PCl (1c) proceeds less selectively. Reactions with metal oxides under aprotic conditions provide 2a [impure, from 1a with (nBu3Sn)2O] and 2b [from iodophosphaalkene (iPrMe2Si)2C=PI with Ag2O] as oils. 1H, 13C, 29Si and 31P NMR spectra, however, allow unambiguous characterisation of 2a and 2b. Formation mechanisms, structure, and C=P-O π stabilisation of the oxabisphosphaalkene [(H3Si)2C=P]2O (2ʹ) were studied with DFT methods. The double [2+4] cycloaddition reaction of 2a with two equivalents of cyclopentadiene leads to the phosphinous anhydride 7 as a mixture of diastereomers whereas the addition of two equivalents of tetrachloro-o-benzoquinone proceeds in a diastereoselective fashion. An X-ray crystal structure determination of the resulting oxo-bridged bis(2-phospha-2,5-dioxa-3,4-benzophospholene) derivative 8 revealed the presence of a racemic mixture of (R,R)- and (S,S)-configurated molecules. The solid state structure of a by-product, bisylphosphonic tetrachlorocatechol monoester (Me3Si)2CH-P(=O)(OH)-o-OC6Cl4OH 9, was also determined crystallographically.

Copper and zinc complexes of a diaza-crown ether as artificial nucleases for the efficient hydrolytic cleavage of DNA

2015 ◽  
Vol 39 (7) ◽  
pp. 5654-5660 ◽  
Author(s):  
Fang-zhen Li ◽  
Jia-qing Xie ◽  
Fa-mei Feng
Keyword(s):  
Crown Ether ◽  
Zinc Complexes ◽  
Hydrolytic Cleavage ◽  
Copper And Zinc ◽  
Artificial Nucleases

Copper and zinc complexes of a diaza-crown ether, serving as artificial nucleases, exhibited high nuclease activities towards the hydrolytic cleavage of DNA.

scholarly journals Hydrolysis of the RNA model substrate catalyzed by a binuclear ZrIV-substituted Keggin polyoxometalate

2015 ◽  
Vol 44 (35) ◽  
pp. 15690-15696 ◽  
Author(s):  
Thi Kim Nga Luong ◽  
Gregory Absillis ◽  
Pavletta Shestakova ◽  
Tatjana N. Parac-Vogt
Keyword(s):  
Kinetics And Thermodynamics ◽  
Nitrophenyl Phosphate ◽  
Keggin Polyoxometalate ◽  
Hydrolysis Of

The kinetics and thermodynamics of 2-hydroxypropyl-4-nitrophenyl phosphate (HPNP) hydrolysis catalyzed by the binuclear ZrIV-substituted Keggin polyoxometalate (Et2NH2)8[{α-PW11O39Zr(μ-OH)(H2O)}2]·7H2O were fully reported.

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