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Journal articles on the topic 'Catalyse or'

Author: Grafiati

Published: 7 July 2024

Last updated: 31 July 2025

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1

Rajesh, Nimmakuri, and Dipak Prajapati. "Indium(iii) catalysed regio- and stereoselective hydrothiolation of bromoalkynes." RSC Adv. 4, no. 61 (2014): 32108–12. http://dx.doi.org/10.1039/c4ra04359f.

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Hydrothiolation of bromoalkynes has been reported for the first time under metal catalysed conditions. Indium(iii) trifluoromethanesulfonate was demonstrated as the first catalyst which can catalyse the hydrothiolation of bromoalkynes with absolute regio- and stereoselectivity to generate synthetically valuable (Z)-β-bromo vinyl sulfides in good yields.

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2

Avigliano, L., V. Carelli, A. Casini, A. Finazzi-Agrò, and F. Liberatore. "Oxidation of NAD dimers by horseradish peroxidase." Biochemical Journal 226, no. 2 (1985): 391–95. http://dx.doi.org/10.1042/bj2260391.

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Horseradish peroxidase catalyses the oxidation of NAD dimers, (NAD)2, to NAD+ in accordance with a reaction that is pH-dependent and requires 1 mol of O2 per 2 mol of (NAD)2. Horseradish peroxidase also catalyses the peroxidation of (NAD)2 to NAD+. In contrast, bacterial NADH peroxidase does not catalyse the peroxidation or the oxidation of (NAD)2. A free-radical mechanism is proposed for both horseradish-peroxidase-catalysed oxidation and peroxidation of (NAD)2.

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3

Al-Taie, Zahraa S., Simon J. Coles, Aileen Congreve, et al. "C2-Symmetric Amino Acid Amide-Derived Organocatalysts." Reactions 5, no. 3 (2024): 567–86. http://dx.doi.org/10.3390/reactions5030027.

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N-alkylated C2-symmetric amino acid amide derivatives were shown to catalyse the Michael addition of 2-hydroxy-1,4-napthoquinone to β-nitrostyrene, achieving a maximum ee of 44%. The corresponding trifluoroacetic acid salts also catalysed the aldol reaction between 4-nitrobenzaldehyde and hydroxyacetone, leading to the formation of predominantly syn-aldol products in up to 55% ee. Aspects of the solvent dependence of the aldol reaction and the H-bonding of the catalyst were investigated.

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4

Liu, Yansheng, Xinlin Li, Xuanduong Le, et al. "Catalysis of the hydro-dechlorination of 4-chlorophenol by Pd(0)-modified MCM-48 mesoporous microspheres with an ultra-high surface area." New Journal of Chemistry 39, no. 6 (2015): 4519–25. http://dx.doi.org/10.1039/c5nj00617a.

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5

Jia, Yunhua, Takeo Tomita, Kazuma Yamauchi, Makoto Nishiyama, and David R. J. Palmer. "Kinetics and product analysis of the reaction catalysed by recombinant homoaconitase from Thermus thermophilus." Biochemical Journal 396, no. 3 (2006): 479–85. http://dx.doi.org/10.1042/bj20051711.

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HACN (homoaconitase) is a member of a family of [4Fe-4S] cluster-dependent enzymes that catalyse hydration/dehydration reactions. The best characterized example of this family is the ubiquitous ACN (aconitase), which catalyses the dehydration of citrate to cis-aconitate, and the subsequent hydration of cis-aconitate to isocitrate. HACN is an enzyme from the α-aminoadipate pathway of lysine biosynthesis, and has been identified in higher fungi and several archaea and one thermophilic species of bacteria, Thermus thermophilus. HACN catalyses the hydration of cis-homoaconitate to (2R,3S)-homoisoc

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6

Gu, Nina X., Gaël Ung, and Jonas C. Peters. "Catalytic hydrazine disproportionation mediated by a thiolate-bridged VFe complex." Chemical Communications 55, no. 37 (2019): 5363–66. http://dx.doi.org/10.1039/c9cc00345b.

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A heterobimetallic VFe complex is demonstrated to catalyse hydrazine disproportionation with yields of up to 1073 equivalents of NH<sub>3</sub> per catalyst, comparable to the highest turnover known for any molecular catalyst.

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7

Giger, Rudolf, and Pascal Hoffmann. "Design and synthesis of a transition state analog of a metalloporphyrin-catalysed oxidation reaction." Journal of Porphyrins and Phthalocyanines 06, no. 05 (2002): 362–65. http://dx.doi.org/10.1142/s1088424602000439.

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A hapten that mimics the transition state of a metalloporphyrin-catalysed oxidation reaction was synthesized in order to generate antibodies that might be able to catalyse the regioselective metalloporphyrin-co-catalysed reaction of cyclosporin A to [D-Ser8]cyclosporin A.

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8

Zhang, Yu Li, Xiang Ying Hao, Cui Zhang, and De Yun Ma. "Application of SO₄^2-/ Al-Fe-Activated Solid Acid Catalyst Prepared by Cross-Linking Method." Applied Mechanics and Materials 448-453 (October 2013): 2929–32. http://dx.doi.org/10.4028/www.scientific.net/amm.448-453.2929.

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SO42-/ Al-Fe-activated solid acid catalyst has been prepared using cross-linking method, and characterized by FTIR spectra, TG-DTA, XRD analysis. The catalyst is able to effectively catalyse the hydration of turpentine to α-terpineol, with the conversion up to 40% after > 4 uses.

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9

Martínez, Alejandro V., Fabio Invernizzi, Alejandro Leal-Duaso, José A. Mayoral, and José I. García. "Microwave-promoted solventless Mizoroki–Heck reactions catalysed by Pd nanoparticles supported on laponite clay." RSC Advances 5, no. 14 (2015): 10102–9. http://dx.doi.org/10.1039/c4ra15418e.

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Palladium nanoparticles supported on laponite efficiently catalyse solventless Mizoroki–Heck reactions activated by microwaves. High yields are obtained in a few minutes and the catalyst can be efficiently recovered and reused up to thirteen times.

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10

BAGGOTT, Joseph E., and Robert E. MacKENZIE. "5,10-Methenyltetrahydrofolate cyclohydrolase, rat liver and chemically catalysed formation of 5-formyltetrahydrofolate." Biochemical Journal 374, no. 3 (2003): 773–78. http://dx.doi.org/10.1042/bj20021970.

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The 5,10-methenyltetrahydrofolate (5,10-CH=H4folate) synthetase catalyses the physiologically irreversible formation of 5,10-CH=H4folate from 5-formyltetrahydrofolate (5-HCO-H4folate) and ATP. It is not clear how (or if) 5-HCO-H4folate is formed in vivo. Using a spectrophotometric assay for 5-HCO-H4folate, human recombinant 5,10-CH=H4folate cyclohydrolase, which catalyses the hydrolysis of 5,10-CH=H4folate to 10-HCO-H4folate, was previously shown to catalyse inefficiently the formation of 5-HCO-H4folate at pH 7.3 [Pelletier and MacKenzie (1996) Bioorg. Chem. 24, 220–228]. In the present study,

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11

BERTOLDI, Mariarita, Virginia CARBONE та Carla BORRI VOLTATTORNI. "Ornithine and glutamate decarboxylases catalyse an oxidative deamination of their α-methyl substrates". Biochemical Journal 342, № 3 (1999): 509–12. http://dx.doi.org/10.1042/bj3420509.

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Ornithine decarboxylase (ODC) from Lactobacillus 30a catalyses the cleavage of α-methylornithine into ammonia and 2-methyl-1-pyrroline; glutamate decarboxylase (GAD) from Escherichia coli catalyses the cleavage of α-methylglutamate into ammonia and laevulinic acid. In our analyses, 2-methyl-1-pyrroline and laevulinic acid were identified by HPLC and mass spectroscopic analysis, and ammonia was identified by means of glutamate dehydrogenase. Molecular oxygen was consumed during these reactions in a 1:2 molar ratio with respect to the products. The catalytic efficiencies (kcat/Km) of the reactio

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12

MONTE, Massimo DAL, Ilaria CECCONI, Francesca BUONO, Pier Giuseppe VILARDO, Antonella DEL CORSO, and Umberto MURA. "Thioltransferase activity of bovine lens glutathione S-transferase." Biochemical Journal 334, no. 1 (1998): 57–62. http://dx.doi.org/10.1042/bj3340057.

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A Mu-class glutathione S-transferase purified to electrophoretic homogeneity from bovine lens displayed thioltransferase activity, catalysing the transthiolation reaction between GSH and hydroxyethyldisulphide. The thiol-transfer reaction is composed of two steps, the formation of GSSG occurring through the generation of an intermediate mixed disulphide between GSH and the target disulphide. Unlike glutaredoxin, which is only able to catalyse the second step of the transthiolation process, glutathioneS-transferase catalyses both steps of the reaction. Data are presented showing that bovine len

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13

Han, Fei, Wenrui Wang, Danyi Li, et al. "Green preparation of silver nanocluster composite AgNCs@CF-g-PAA and its application: 4-NP catalytic reduction and hydrogen production." RSC Advances 13, no. 17 (2023): 11807–16. http://dx.doi.org/10.1039/d3ra01245j.

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Silver nanocluster composites are obtained directly through radiation technology and can be used to catalyse 4-nitrophenol reduction and sodium borohydride. The catalyst is a candidate for the treatment of water contaminant 4-NP and the production of hydrogen from NaBH4.

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14

Chen, Gong-Jun, Chao-Qun Chen, Xue-Tian Li, Hui-Chao Ma, and Yu-Bin Dong. "Cu3L2 metal–organic cages for A3-coupling reactions: reversible coordination interaction triggered homogeneous catalysis and heterogeneous recovery." Chemical Communications 54, no. 82 (2018): 11550–53. http://dx.doi.org/10.1039/c8cc07208f.

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A novel Cu<sub>3</sub>L<sub>2</sub> metal–organic cage, which features coordination interaction triggered solubility, can be a highly active and reusable catalyst to homogeneously catalyse the one-pot aldehyde–alkyne–amine A<sup>3</sup>-coupling reaction.

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15

Villemin, Didier, and Endo Schigeko. "Catalyse homogene: Synthese des benchrotrenylacetylenes catalysee par le palladium." Journal of Organometallic Chemistry 293, no. 1 (1985): C10—C12. http://dx.doi.org/10.1016/0022-328x(85)80256-4.

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16

Zhang, Zhi, Zhihang Huang, and Hong Yuan. "Direct conversion of cellulose to ethyl levulinate catalysed by modified fibrous mesoporous silica nanospheres in a co-solvent system." New Journal of Chemistry 45, no. 12 (2021): 5526–39. http://dx.doi.org/10.1039/d0nj05433j.

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A KCC-1/Al–SO<sub>3</sub>H catalyst with Si/Al = 5 was prepared to directly catalyse the synthesis of ethyl levulinate from cellulose in an ethanol/toluene co-solvent system. A reaction yield of 28.8 mol% was achieved after 6 h at 200 °C.

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17

Ghosh, Shishir, Graeme Hogarth, Nathan Hollingsworth, Katherine B. Holt, Shariff E. Kabir та Ben E. Sanchez. "Hydrogenase biomimetics: Fe2(CO)4(μ-dppf)(μ-pdt) (dppf = 1,1′-bis(diphenylphosphino)ferrocene) both a proton-reduction and hydrogen oxidation catalyst". Chem. Commun. 50, № 8 (2014): 945–47. http://dx.doi.org/10.1039/c3cc46456c.

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The diiron complex Fe<sub>2</sub>(CO)<sub>4</sub>(μ-dppf)(μ-pdt) is an active catalyst for both the reduction of protons to give hydrogen and also the reverse oxidation of hydrogen and thus mimics hydrogenases which are able to catalyse both reactions.

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18

Hiller, David A., and Scott A. Strobel. "The chemical versatility of RNA." Philosophical Transactions of the Royal Society B: Biological Sciences 366, no. 1580 (2011): 2929–35. http://dx.doi.org/10.1098/rstb.2011.0143.

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The ability of RNA to both store genetic information and catalyse chemical reactions has led to the hypothesis that it predates DNA and proteins. While there is no doubt that RNA is capable of storing the genetic information of a primitive organism, only two classes of reactions—phosphoryl transfer and peptide bond formation—have been observed to be catalysed by RNA in nature. However, these naturally occurring ribozymes use a wide range of catalytic strategies that could be applied to other reactions. Furthermore, RNA can bind several cofactors that are used by protein enzymes to facilitate a

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19

Arabczyk, Walerian, Urszula Narkiewicz, Zofia Lendzion-Bieluń, et al. "Utilization of spent iron catalyst for ammonia synthesis." Polish Journal of Chemical Technology 9, no. 3 (2007): 108–13. http://dx.doi.org/10.2478/v10026-007-0067-y.

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Utilization of spent iron catalyst for ammonia synthesis Several methods of the utilization of spent iron catalyst for ammonia synthesis have been presented. The formation of iron nitrides of different stoichiometry by direct nitriding in ammonia in the range of temperatures between 350°C and 450°C has been shown. The preparation methods of carbon nanotubes and nanofibers where iron catalyst catalyse the decomposition of hydrocarbons have been described. The formation of magnetite embedded in a carbon material by direct oxidation of carburized iron catalyst has been also presented.

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20

Banerjee, R., and M. Vlasie. "Controlling the reactivity of radical intermediates by coenzyme B12-dependent methylmalonyl-CoA mutase." Biochemical Society Transactions 30, no. 4 (2002): 621–24. http://dx.doi.org/10.1042/bst0300621.

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Adenosylcobalamin or coenzyme B12-dependent enzymes are members of the still relatively small group of radical enzymes and catalyse 1,2-rearrangement reactions. A member of this family is methylmalonyl-CoA mutase, which catalyses the isomerization of methylmalonyl-CoA to succinyl-CoA and, unlike the others, is present in both bacteria and animals. Enzymes that catalyse some of the most chemically challenging reactions are the ones that tend to deploy radical chemistry. The use of radical intermediates in an active site lined with amino acid side chains that threaten to extinguish the reaction

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21

Dembinski, Paul H. "Crise ou catalyse ?" Finance & Bien Commun 31-32, no. 2 (2008): 11. http://dx.doi.org/10.3917/fbc.031.0011.

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22

Khan, Mohammad Niyaz, and Ibrahim Isah Fagge. "Kinetics and Mechanism of Cationic Micelle/Flexible Nanoparticle Catalysis: A Review." Progress in Reaction Kinetics and Mechanism 43, no. 1 (2018): 1–20. http://dx.doi.org/10.3184/146867818x15066862094905.

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The aqueous surfactant (Surf) solution at [Surf] > cmc (critical micelle concentration) contains flexible micelles/nanoparticles. These particles form a pseudophase of different shapes and sizes where the medium polarity decreases as the distance increases from the exterior region of the interface of the Surf/H2O particle towards its furthest interior region. Flexible nanoparticles (FNs) catalyse a variety of chemical and biochemical reactions. FN catalysis involves both positive catalysis ( i.e. rate increase) and negative catalysis ( i.e. rate decrease). This article describes the mechani

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23

Ma, Yubo, Zhixian Gao, Tao Yuan, and Tianfu Wang. "Kinetics of Dicyclopentadiene Hydroformylation over Rh–SiO2 Catalysts." Progress in Reaction Kinetics and Mechanism 42, no. 2 (2017): 191–99. http://dx.doi.org/10.3184/146867817x14821527549013.

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The hydroformylation of dicyclopentadiene (DCPD) to monoformyltricyclodecenes (MFTD) represents a key intermediate step in the conversion of the C5 fraction derived from the petrochemical process to value-added fine chemicals, for example, diformyltricyclodecanes and tricyclodecanedimethylol. Although both heterogeneous and homogeneous catalysts can catalyse this reaction, the heterogeneously catalysed pathway has received significantly less attention due to its lower catalytic activities. We demonstrate in this work that a low Rh loaded heterogeneous 0.1% Rh–SiO2 catalyst can present a simila

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24

Wong, W.-Y., S. Lim, Y.-L. Pang, C.-H. Lim, F.-L. Pua, and G. Pua. "Response surface optimisation of biodiesel synthesis using biomass derived green heterogeneous catalyst." IOP Conference Series: Materials Science and Engineering 1257, no. 1 (2022): 012010. http://dx.doi.org/10.1088/1757-899x/1257/1/012010.

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Abstract Although homogeneous alkali-catalysed transesterification is the typical process used in biodiesel production, it caused complications in downstream separation processes and an oversupply of glycerol as a by-product. The present work studied the synthesis of a novel sulfonated biomass-derived solid acid catalyst and its application in biodiesel production via interesterification of oleic acid. Solid acid catalysts were prepared by direct sulfonation via thermal treatment with concentrated sulfuric acid. The design of experiments was conducted via four-factors central composite design

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25

Miłek, J., M. Wójcik, and W. Verschelde. "Thermal stability for the effective use of commercial catalase." Polish Journal of Chemical Technology 16, no. 4 (2014): 75–79. http://dx.doi.org/10.2478/pjct-2014-0073.

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Abstract Catalase with the commercial catalase name Terminox Ultra is widely used in the textile industry in bleaching processes. This enzyme is used to catalyse the decomposition of residual hydrogen peroxide into oxygen and water. In this study catalase was kept for about 30 hours in water baths in a temperature range from 35 to 70°C. For the first time, the kinetics of thermal deactivation of this enzyme was examined using an oxygen electrode. Stability of the enzyme depends strongly on temperature and its half-life times are 0.0014 h and 7.6 h, at 35 and 70°C, respectively.

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26

Jankovič, Ľuboš, and Peter Komadel. "Catalytic Properties of a Heated Ammonium-Saturated Dioctahedral Smectite." Collection of Czechoslovak Chemical Communications 65, no. 9 (2000): 1527–36. http://dx.doi.org/10.1135/cccc20001527.

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A series of acid catalysts was prepared by heating of NH4-saturated montmorillonite at 200-600 °C for 24 h. Their catalytic activity was tested in acetylation of 3,4,5-trimethoxybenzaldehyde with acetic anhydride. This reaction is sufficiently sensitive to modification of the catalyst and thus suitable for testing catalytic activity of modified montmorillonites. Most of the prepared catalysts were able to catalyse the test reaction and produce diacetate in higher than 50% yields. The most active catalyst was obtained after heating at 300 °C. It was slightly less effective than commercially ava

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27

Maia, Luisa B. "Bringing Nitric Oxide to the Molybdenum World—A Personal Perspective." Molecules 28, no. 15 (2023): 5819. http://dx.doi.org/10.3390/molecules28155819.

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Molybdenum-containing enzymes of the xanthine oxidase (XO) family are well known to catalyse oxygen atom transfer reactions, with the great majority of the characterised enzymes catalysing the insertion of an oxygen atom into the substrate. Although some family members are known to catalyse the “reverse” reaction, the capability to abstract an oxygen atom from the substrate molecule is not generally recognised for these enzymes. Hence, it was with surprise and scepticism that the “molybdenum community” noticed the reports on the mammalian XO capability to catalyse the oxygen atom abstraction o

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28

Boucher, Guillaume, Bilal Said, Elizabeth L. Ostler, Marina Resmini, Keith Brocklehurst, and Gerard Gallacher. "Evidence that the mechanism of antibody-catalysed hydrolysis of arylcarbamates can be determined by the structure of the immunogen used to elicit the catalytic antibody." Biochemical Journal 401, no. 3 (2007): 721–26. http://dx.doi.org/10.1042/bj20060551.

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A kinetically homogeneous anti-phosphate catalytic antibody preparation was shown to catalyse the hydrolysis of a series of O-aryl N-methyl carbamates containing various substituents in the 4-position of the O-phenyl group. The specific nature of the antibody catalysis was demonstrated by the adherence of these reactions to the Michaelis–Menten equation, the complete inhibition by a hapten analogue, and the failure of the antibody to catalyse the hydrolysis of the 2-nitrophenyl analogue of the 4-nitrophenylcarbamate substrate. Hammett σ–ρ analysis suggests that both the non-catalysed and antib

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29

Nadirova, Maryana, Joel Cejas-Sánchez, Rosa María Sebastián, et al. "Synthesis of Phenol-Tagged Ruthenium Alkylidene Olefin Metathesis Catalysts for Robust Immobilisation Inside Metal–Organic Framework Support." Catalysts 13, no. 2 (2023): 297. http://dx.doi.org/10.3390/catal13020297.

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Two new unsymmetrical N-heterocyclic carbene ligand (uNHC)-based ruthenium complexes featuring phenolic OH function were obtained and fully characterised. The more active one was then immobilised on the metal–organic framework (MOF) solid support (Al)MIL-101-NH2. The catalytic activity of such a heterogeneous system was tested, showing that, while the heterogeneous catalyst is less active than the corresponding homogeneous catalyst in solution, it can catalyse selected olefin metathesis reactions, serving as the proof-of-concept for the immobilisation of catalytically active complexes in MOFs

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30

Lalanne-Tisné, Michael, Audrey Favrelle-Huret, Wim Thielemans, João P. Prates Ramalho, and Philippe Zinck. "DFT Investigations on the Ring-Opening Polymerization of Trimethylene Carbonate Catalysed by Heterocyclic Nitrogen Bases." Catalysts 12, no. 10 (2022): 1280. http://dx.doi.org/10.3390/catal12101280.

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Organocatalysts for polymerization have known a huge interest over the last two decades. Among them, heterocyclic nitrogen bases are widely used to catalyse the ring-opening polymerization (ROP) of heterocycles such as cyclic carbonates. We have investigated the ring-opening polymerization of trimethylene carbonate (TMC) catalysed by DMAP (4-dimethylaminopyridine) and TBD (1,5,7-triazabicyclo[4.4.0]dec-5-ene) as case studies in the presence of methanol as co-initiator by Density Functional Theory (DFT). A dual mechanism based on H-bond activation of the carbonyl moieties of the monomer and a b

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31

Wijayati, Nanik, Harno Dwi Pranowo, Jumina Jumina та Triyono Triyono. "SYNTHESIS OF TERPINEOL FROM α-PINENE CATALYZED BY TCA/Y-ZEOLITE". Indonesian Journal of Chemistry 11, № 3 (2011): 234–37. http://dx.doi.org/10.22146/ijc.21386.

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The hydration of a-pinene has been studied in the presence of TCA/Y-Zeolite catalyse. The catalyst was prepared by impregnating trichloroacetic acid (TCA) on support of Y-Zeolite. The TCA/Y-Zeolite catalyst converted a-pinene into hydrocarbons, while the TCA/Y-Zeolite catalyst was active and selective for producing alcohols, with a conversion of 66% and showed 55% selectivity for α-terpineol at 10 min. The reaction taken place in a solid-liquid mode and most of the α-terpineol is extracted out by the organic phase during the course of the reaction. TCA/Y-Zeolite was found as good catalyst for

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32

ABBADI, Amine, Monika BRUMMEL, Burkhardt S. SCHüTT, Mary B. SLABAUGH, Ricardo SCHUCH, and Friedrich SPENER. "Reaction mechanism of recombinant 3-oxoacyl-(acyl-carrier-protein) synthase III from Cuphea wrightii embryo, a fatty acid synthase type II condensing enzyme." Biochemical Journal 345, no. 1 (1999): 153–60. http://dx.doi.org/10.1042/bj3450153.

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A unique feature of fatty acid synthase (FAS) type II of higher plants and bacteria is 3-oxoacyl-[acyl-carrier-protein (ACP)] synthase III (KAS III), which catalyses the committing condensing reaction. Working with KAS IIIs from Cuphea seeds we obtained kinetic evidence that KAS III catalysis follows a Ping-Pong mechanism and that these enzymes have substrate-binding sites for acetyl-CoA and malonyl-ACP. It was the aim of the present study to identify these binding sites and to elucidate the catalytic mechanism of recombinant Cuphea wrightii KAS III, which we expressed in Escherichia coli. We

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33

Villemin, Didier, та Endo Schigeko. "Catalyse homogéné: synthèse d'organométalliques σ-acétylèniques catalysée par le cuivre(I)". Journal of Organometallic Chemistry 346, № 1 (1988): C24—C26. http://dx.doi.org/10.1016/0022-328x(88)87018-9.

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34

Dubied, Annik. "Catalyse et parenthèse enchantée." Le Temps des médias 10, no. 1 (2008): 142. http://dx.doi.org/10.3917/tdm.010.0142.

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35

Kentish, Sandra. "Embedded enzymes catalyse capture." Nature Energy 3, no. 5 (2018): 359–60. http://dx.doi.org/10.1038/s41560-018-0146-8.

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36

Kruyt, H. R., and C. F. van Duin. "Catalyse Hétérogène et Adsorption." Recueil des Travaux Chimiques des Pays-Bas 40, no. 5 (2010): 249–80. http://dx.doi.org/10.1002/recl.19210400502.

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37

Newsholme, Philip. "Mapping life's reactions: A brief history of metabolic pathways and their regulation." Biochemist 31, no. 3 (2009): 4–7. http://dx.doi.org/10.1042/bio03103004.

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It is now recognized that almost all chemical reactions that take place in a living cell require an enzyme to catalyse the reaction. An enzyme catalyses one (or, in rare cases, more than one closely related) chemical reaction. The complete synthesis or degradation of complex biological substances such as glycogen, nucleic acids, proteins and lipids requires a series of linked sequences of reactions. A chain of such reactions is referred to as a ‘metabolic pathway’.

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38

Thomas, Stephen, Nate Ang, Cornelia Buettner, et al. "Borane-Catalysed Hydroboration of Alkynes and Alkenes." Synthesis 50, no. 04 (2017): 803–8. http://dx.doi.org/10.1055/s-0036-1591719.

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Simple, commercially available borane adducts, H3B·THF and H3B·SMe2, have been used to catalyse the hydroboration of alkynes and alkenes with pinacolborane to give the alkenyl and alkyl boronic esters, respectively. Alkynes and terminal alkenes underwent highly regioselective hydroboration to give the linear boronic ester products. Good functional group tolerance was observed for substrates bearing ester, amine, ether and halide substituents. This catalytic process shows comparable reactivity to transition-metal-catalysed hydroboration protocols.

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39

Mantle, T. J. "Haem degradation in animals and plants." Biochemical Society Transactions 30, no. 4 (2002): 630–33. http://dx.doi.org/10.1042/bst0300630.

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Two enzyme systems have evolved for the reduction of linear tetrapyrroles: one family, found in plants, algae and cyanobacteria, uses ferredoxin and catalyses the reduction of the terminal pyrrole rings (A and D) and one of the vinyl side chains to form various light-harvesting and light-sensing chromophores. The other group (biliverdin reductases A and B) utilize NAD(P)H and catalyse reduction at C10 (hydride addition) to form the ‘bile’ pigments bilirubin-IXα and bilirubin-IX.

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Yang, Ren-Qiang, Ni Zhang, Xiang-Guang Meng, Xiao-Hong Liao, Lu Li та Hong-Jin Song. "Efficient Hydrolytic Breakage of β-1,4-Glycosidic Bond Catalyzed by a Difunctional Magnetic Nanocatalyst". Australian Journal of Chemistry 71, № 8 (2018): 559. http://dx.doi.org/10.1071/ch18138.

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A novel difunctional magnetic nanocatalyst (DMNC) was prepared and used to catalyse the hydrolytic breakage of β-1,4-glycosidic bonds. The functional nanoparticle displayed excellent catalytic activity for hydrolysis of cellobiose to glucose under moderate conditions. The conversion of cellobiose and yield of glucose could reach 95.3 and 91.1 %, respectively, for a reaction time of 6 h at pH 4.0 and 130°C. DMNC was also an efficient catalyst for the hydrolysis of cellulose: 53.9 % microcrystalline cellulose was hydrolyzed, and 45.7 % reducing sugar was obtained at pH 4.0 and 130°C after 10 h.

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Stromnova, Tatiana A. "Palladium(+1) Carbonyl Clusters in the Catalytic Oxidation of Unsaturated Compounds." Platinum Metals Review 47, no. 1 (2003): 20–27. http://dx.doi.org/10.1595/003214003x4712027.

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Some palladium carbonyl clusters containing the palladium in the (+1) formal oxidation state, and derivatives of these clusters investigated in our laboratories are examined in this paper. In particular, letranuclear carbonyl carboxylates of palladium are discussed as a model of key intermediates in various processes, including CO oxidation by a palladium catalyst with molecular oxygen as the oxidant. A second type of cluster, a palladium cationic cluster which contains N-donor ligands acts as a catalyst precursor for processes such as exhaust gas purification. A third type of palladium carbon

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42

Gowri Krishnan, Shamala, Fei Ling Pua, Kumaran Palanisamy, and Sharifah Nabihah. "Preparation of Oil Palm EFB Derived Solid Acid Catalyst for Esterification Reaction: Effect of Calcination Temperature." Key Engineering Materials 701 (July 2016): 117–21. http://dx.doi.org/10.4028/www.scientific.net/kem.701.117.

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Oil palm empty fruit bunch (EFB) is one of the palm biomass produced in abundance after oil extraction in Malaysia. This study was focused to utilize this waste biomass as a beneficial raw materials. EFB was used to prepare new solid acid catalyst for biodiesel production. EFB was converted into solid catalyst via direct impregnation method and it was used to catalyse esterification of oleic acid. Transition metal sulfide salt, Fe2(SO4)3 was impregnated on EFB fibres. Effect of different calcination temperature was studied on the properties of catalyst. The result shows that Fe2(SO4)3 based so

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McCabe, A. R., and G. D. W. Smith. "The Chemical Characterisation of Rhodium-Platinum Surfaces." Platinum Metals Review 32, no. 1 (1988): 11–18. http://dx.doi.org/10.1595/003214088x3211118.

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During the manufacture of nitric acid, rhodium-platinum gauzes are used to catalyse the oxidation of ammonia, an operation that results in a major reconstruction of the alloy surface. In this study, the effect of pretreatments, similar to those employed to prepare the catalysts for commercial use, have been examined to determine both the chemical and the physical effects on the surface. A successful pretreatment is shown to produce a generally clean, chemically receptive surface containing reactive crystal orientation sites. Additionally, the nature of the surface during catalyst operation has

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Malthouse, J. P. G., J. J. Milne, and L. S. Gariani. "A comparative study of the kinetics and stereochemistry of the serine hydroxymethyltransferase- and tryptophan synthase-catalysed exchange of the pro-2R and pro-2S protons of glycine." Biochemical Journal 274, no. 3 (1991): 807–12. http://dx.doi.org/10.1042/bj2740807.

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The stereospecificity of the serine hydroxymethyltransferase (EC 2.1.2.1)- and tryptophan synthase (EC 4.2.1.20)- catalysed exchange of the pro-2R and pro-2S alpha-protons of glycine was investigated by using 13C n.m.r. The exchange process is described in terms of a minimal four-step mechanism, and a method for analysing the exchange process by complete progress curves is presented. It is shown that serine hydroxymethyltransferase does not have absolute stereospecificity for the pro-2S-proton of glycine, but it catalyses the exchange of this proton 7400 times faster than the pro-2R proton of

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Page, Michael I. "The Reactivity of β-Lactams, the Mechanism of Catalysis and the Inhibition of &#946-Lactamases". Current Pharmaceutical Design 5, № 11 (1999): 895–913. http://dx.doi.org/10.2174/1381612805666230112192319.

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Four membered -lactam rings do not show unusual reactivity compared with their acyclic amide analogues and there is no evidence of concerted mechanisms for nucleophilic substitution reactions at the carbonyl centre. The identity of the general base/acid catalyst in the serine &#946;-lactamases, which catalyse the hydrolysis of &#946;-lactams, is unknown. There are no ideal transition state analogue inhibitors for these enzymes which involve several intermediates and transition states. The class C serine &#946;-lactamase enhances the rate of phosphonylation of its active site serine

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D'ANDREA, Sabine, Hervé GUILLOU, Sophie JAN та ін. "The same rat Δ6-desaturase not only acts on 18- but also on 24-carbon fatty acids in very-long-chain polyunsaturated fatty acid biosynthesis". Biochemical Journal 364, № 1 (2002): 49–55. http://dx.doi.org/10.1042/bj3640049.

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The recently cloned Δ6-desaturase is known to catalyse the first step in very-long-chain polyunsaturated fatty acid biosynthesis, i.e. the desaturation of linoleic and α-linolenic acids. The hypothesis that this enzyme could also catalyse the terminal desaturation step, i.e. the desaturation of 24-carbon highly unsaturated fatty acids, has never been elucidated. To test this hypothesis, the activity of rat Δ6-desaturase expressed in COS-7 cells was investigated. Recombinant Δ6-desaturase expression was analysed by Western blot, revealing a single band at 45kDa. The putative involvement of this

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Tabita, F. Robert, Thomas E. Hanson, Sriram Satagopan, Brian H. Witte, and Nathan E. Kreel. "Phylogenetic and evolutionary relationships of RubisCO and the RubisCO-like proteins and the functional lessons provided by diverse molecular forms." Philosophical Transactions of the Royal Society B: Biological Sciences 363, no. 1504 (2008): 2629–40. http://dx.doi.org/10.1098/rstb.2008.0023.

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Ribulose 1,5-bisphosphate (RuBP) carboxylase/oxygenase (RubisCO) catalyses the key reaction by which inorganic carbon may be assimilated into organic carbon. Phylogenetic analyses indicate that there are three classes of bona fide RubisCO proteins, forms I, II and III, which all catalyse the same reactions. In addition, there exists another form of RubisCO, form IV, which does not catalyse RuBP carboxylation or oxygenation. Form IV is actually a homologue of RubisCO and is called the RubisCO-like protein (RLP). Both RubisCO and RLP appear to have evolved from an ancestor protein in a methanoge

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Tang, B., S. Zhang, and K. Yang. "Assisted refolding of recombinant prochymosin with the aid of protein disulphide isomerase." Biochemical Journal 301, no. 1 (1994): 17–20. http://dx.doi.org/10.1042/bj3010017.

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Protein disulphide isomerase (PDI) was shown to be able to accelerate the refolding of unfolded recombinant prochymosin and to enhance the overall yield of active protein. Unlike previous reports in this study PDI was found to be active at pH values as high as 11. The coincidence of the similar apparent optimum pH values of uncatalysed and PDI-catalysed reactions suggests that conditions favourable to spontaneous refolding of proteins may help PDI to catalyse thiol/disulphide interchange. Under the conditions described here no exogenously added dithiothreitol was required for PDI-catalysed ren

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Ortega-Caballero, Fernando, and Mikael Bols. "Cyclodextrin derivatives with cyanohydrin and carboxylate groups as artificial glycosidases." Canadian Journal of Chemistry 84, no. 4 (2006): 650–58. http://dx.doi.org/10.1139/v06-039.

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Two cyclodextrin derivatives (1 and 2) were prepared in an attempt to create glycosidase mimics with a general acid catalyst and a nucleophilic carboxylate group. The catalysts 1 and 2 were found to catalyse the hydrolysis of 4-nitrophenyl β-D-glucopyranoside at pH 8.0, but rapidly underwent decomposition with loss of hydrogen cyanide to convert the cyanohydrin to the corresponding aldehyde. The initial rate of the catalysis shows that the cyanohydrin group in these molecules functions as a good catalyst, but that the carboxylate has no positive effect. The decomposition product aldehydes disp

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Tiano, Martin. "Des « gemmes » pour la catalyse." Pour la Science N° 505 - novembre, no. 11 (2019): 9b. http://dx.doi.org/10.3917/pls.505.0009b.

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