Metal substitution in thermolysin: Catalytic properties of tungstate thermolysin in sulfoxidation with H2O2

The catalytic Zn2+ ion was extracted from thermolysin, which had been covalently bound to Eupergit C. The apo-enzyme incorporated the oxometallate anions MoO42, SeO42, and WO42 with partial restoration of the proteolytic activity. Tungstate thermolysin was moderately active in the sulfoxidation of thioanisole by hydrogen peroxide, whereas its activity towards phenylmercaptoacetophenone, which was designed to bind well in the active site of thermolysin, was much higher.

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Decomposition of hydrogen peroxide on a two-component NiO-CdO catalyst and the effect of ionizing radiation on its catalytic properties

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19791015 ◽

1979 ◽

Vol 44 (4) ◽

pp. 1015-1022 ◽

Cited By ~ 7

Author(s):

Viliam Múčka

Keyword(s):

Aqueous Solution ◽

Hydrogen Peroxide ◽

Catalytic Activity ◽

Nickel Oxide ◽

Catalytic Properties ◽

Cadmium Oxide ◽

Chemisorb Oxygen ◽

Composition Region ◽

Chemisorbed Oxygen ◽

Two Component

The catalytic properties of two-component catalyst nickel oxide-cadmium oxide with the proportions of the components covering the whole composition region 0-100% were examined by studying the decomposition of hydrogen peroxide in aqueous solution on it. In the range 0-25 mol.% CdO, cadmium oxide is found to affect infavourably the ability of nickel oxide to chemisorb oxygen. The amount of the chemisorbed oxygen increases several times on gamma irradiation of the samples. The effect of cadmium oxide on the catalytic activity of the system shows up in fresh samples only indirectly via the changed amount of the oxygen chemisorbed. In older samples the initial catalytic activity of the system is changed, which can be explained based on the concept of bivalent catalytic centres in terms of the co-action of the catalytic centres of the two oxides, which are in equilibrium. The irradiation of the system under study speeds up the processes leading to the establishing of this equilibrium which is thermally very stable, and results in a substantial increase of the catalytic activity of the samples investigated.

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Hydrogen peroxide decomposition on a two-component CuO-Cr2O3 catalyst

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19881636 ◽

1988 ◽

Vol 53 (8) ◽

pp. 1636-1646 ◽

Cited By ~ 8

Author(s):

Viliam Múčka ◽

Kamil Lang

Keyword(s):

Hydrogen Peroxide ◽

Catalytic Activity ◽

Extreme Values ◽

Catalytic Properties ◽

Active Components ◽

Catalytic Systems ◽

Heterogeneous Catalytic ◽

Peroxide Decomposition ◽

Two Component ◽

Catalytically Active

Some physical and catalytic properties of the two-component copper(II)oxide-chromium(III)oxide catalyst with different content of both components were studied using the decomposition of the aqueous solution of hydrogen peroxide as a testing reaction. It has been found that along to both basic components, the system under study contains also the spinel structure CuCr2O4, chromate washable by water and hexavalent ions of chromium unwashable by water. The soluble chromate is catalytically active. During the first period of the reaction the equilibrium is being established in both homogeneous and heterogeneous catalytic systems. The catalytic activity as well as the specific surface area of the washed solid is a non-monotonous function of its composition. It seems highly probable that the extreme values of both these quantities are not connected with the detected admixtures in the catalytic system. The system under study is very insensitive with regard to the applied doses of gamma radiation. Its catalytic properties are changed rather significantly after the thermal treatment and particularly after the partial reduction to low degree by hydrogen. The observed changes of the catalytic activity of the system under study are very probably in connection with the changes of the valence state of the catalytically active components of the catalyst.

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Decomposition of hydrogen peroxide on cerium dioxide-nickel oxide two-component catalysts and the effect of ionizing radiation on them

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19840014 ◽

1984 ◽

Vol 49 (1) ◽

pp. 14-24 ◽

Cited By ~ 6

Author(s):

Viliam Múčka

Keyword(s):

Heat Treatment ◽

Hydrogen Peroxide ◽

Ionizing Radiation ◽

Nickel Oxide ◽

Cerium Dioxide ◽

Catalytic Properties ◽

Specific Activity ◽

Ion Pairs ◽

Composition Region ◽

Two Component

Some physical and catalytic properties of cerium dioxide-nickel oxide two-component catalysts have been studied over the entire composition region, employing the decomposition of hydrogen peroxide in aqueous solution as a model catalytic process. The two oxides have been found to affect each other, particularly for NiO contents of 9.1 and 96.7 mol%; the mutual influencing, the nature of which in the conditions applied remains unaffected by heat treatment of the sample or by its exposition to ionizing radiation, is manifested by the nonmonotonic dependences of the oxidation power and of the specific activity of the catalysts on their composition. This can be interpreted in terms of the concept of bivalent catalytic centres, assuming that for nickel oxide the centres consist of Ni2+-Ni3+ ion pairs, for cerium dioxide they consist of Ce3+-Ce4+ ion pairs, and that in the region of the mutual influencing , Ni2+-Ce4+ ion pairs play a major role. Within the scope of this concept, the increase in the oxidation power of all the catalysts in question and a simultaneously decrease in the specific activity of the pure nickeloxide exposed to ionizing radiation can be explained in terms of the ionization effect.

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A comparative study of class-D β-lactamases

Biochemical Journal ◽

10.1042/bj2920555 ◽

1993 ◽

Vol 292 (2) ◽

pp. 555-562 ◽

Cited By ~ 56

Author(s):

P Ledent ◽

X Raquet ◽

B Joris ◽

J Van Beeumen ◽

J M Frère

Keyword(s):

Active Site ◽

Gene Sequence ◽

Catalytic Properties ◽

Ion Exchange Chromatography ◽

Exchange Chromatography ◽

Beta Lactamase ◽

Serine Residue ◽

Beta Lactamases ◽

Class D ◽

Burst Kinetics

Three class-D beta-lactamases (OXA2, OXA1 and PSE2) were produced and purified to protein homogeneity. 6 beta-Iodopenicillanate inactivated the OXA2 enzyme without detectable turnover. Labelling of the same beta-lactamase with 6 beta-iodo[3H]penicillanate allowed the identification of Ser-70 as the active-site serine residue. In agreement with previous reports, the apparent M(r) of the OXA2 enzyme as determined by molecular-sieve filtration, was significantly higher than that deduced from the gene sequence, but this was not due to an equilibrium between a monomer and a dimer. The heterogeneity of the OXA2 beta-lactamase on ion-exchange chromatography contrasted with the similarity of the catalytic properties of the various forms. A first overview of the enzymic properties of the three ‘oxacillinases’ is presented. With the OXA2 enzyme, ‘burst’ kinetics, implying branched pathways, seemed to prevail with many substrates.

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Dual- vs single-active site mechanism in the catalytic decomposition of hydrogen peroxide

Journal of Inorganic and Nuclear Chemistry ◽

10.1016/0022-1902(78)80554-5 ◽

1978 ◽

Vol 40 (6) ◽

pp. 1277-1278 ◽

Cited By ~ 7

Author(s):

Mario Barteri ◽

Marcello Farinella ◽

Basilio Pispisa

Keyword(s):

Hydrogen Peroxide ◽

Active Site ◽

Catalytic Decomposition

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Iron-Imprinted Single-Atomic Site Catalyst-Based Nanoprobe for Detection of Hydrogen Peroxide in Living Cells

Nano-Micro Letters ◽

10.1007/s40820-021-00661-z ◽

2021 ◽

Vol 13 (1) ◽

Author(s):

Zhaoyuan Lyu ◽

Shichao Ding ◽

Maoyu Wang ◽

Xiaoqing Pan ◽

Zhenxing Feng ◽

...

Keyword(s):

Hydrogen Peroxide ◽

Active Site ◽

Single Atom ◽

Site Structure ◽

Atomic Site ◽

Ion Imprinting ◽

Active Site Structure ◽

In Situ Detection ◽

Colorimetric Biosensing

AbstractFe-based single-atomic site catalysts (SASCs), with the natural metalloproteases-like active site structure, have attracted widespread attention in biocatalysis and biosensing. Precisely, controlling the isolated single-atom Fe-N-C active site structure is crucial to improve the SASCs’ performance. In this work, we use a facile ion-imprinting method (IIM) to synthesize isolated Fe-N-C single-atomic site catalysts (IIM-Fe-SASC). With this method, the ion-imprinting process can precisely control ion at the atomic level and form numerous well-defined single-atomic Fe-N-C sites. The IIM-Fe-SASC shows better peroxidase-like activities than that of non-imprinted references. Due to its excellent properties, IIM-Fe-SASC is an ideal nanoprobe used in the colorimetric biosensing of hydrogen peroxide (H2O2). Using IIM-Fe-SASC as the nanoprobe, in situ detection of H2O2 generated from MDA-MB-231 cells has been successfully demonstrated with satisfactory sensitivity and specificity. This work opens a novel and easy route in designing advanced SASC and provides a sensitive tool for intracellular H2O2 detection.

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