scholarly journals Studying the Possibilities of Using 2-Halogen-Substituted Acetamides As Acyl Donors in Penicillin Acylase-Catalyzed Reactions

Acta Naturae ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 77-81
Author(s):  
N. V. Panin ◽  
M. V. Nikulin ◽  
E. S. Tiurin ◽  
V. V. Drobot ◽  
I. A. Morozova ◽  
...  
Keyword(s):  
Alcaligenes Faecalis ◽  
Penicillin Acylase ◽  
Enzyme Inactivation ◽  
Acyl Donor ◽  
Negative Contribution ◽  
Catalyzed Reactions ◽  
The Impact ◽  
Acyl Donors ◽  
Penicillin Acylases ◽  
Acetic Acids

The possibility of using amides of halogen-substituted acetic acids as acyl donors in penicillin acylase-catalyzed reactions has been investigated, and the ability of this group of compounds to inactivate enzymes in the course of the catalytic conversion has been established. The strongest inactivating effect was demonstrated by iodoacetamide and bromoacetamide. However, the negative contribution of this side activity can be minimized by decreasing the temperature, when the rate of acyl donor conversion by penicillin acylases is still high enough, but the impact of enzyme inactivation becomes less significant. The catalytic activity of penicillin acylase from Alcaligenes faecalis in the conversion of 2-haloacetamides was significantly (5-8 times) higher than that of penicillin acylase from Escherichia coli.

International trade: Research of the reasons for the fall

2019 ◽  
pp. 79-91 ◽  
Author(s):  
V. S. Nazarov ◽  
S. S. Lazaryan ◽  
I. V. Nikonov ◽  
A. I. Votinov
Keyword(s):  
Growth Rate ◽  
International Trade ◽  
Exchange Rate ◽  
Global Economy ◽  
Structural Changes ◽  
Global Value Chains ◽  
Value Chains ◽  
Negative Contribution ◽  
Basic Commodity ◽  
The Impact

The article assesses the impact of various factors on the growth rate of international trade. Many experts interpreted the cross-border flows of goods decline against the backdrop of a growing global economy as an alarming sign that indicates a slowdown in the processes of globalization. To determine the reasons for the dynamics of international trade, the decompositions of its growth rate were carried out and allowed to single out the effect of the dollar exchange rate, the commodities prices and global value chains on the change in the volume of trade. As a result, it was discovered that the most part of the dynamics of international trade is due to fluctuations in the exchange rate of the dollar and prices for basic commodity groups. The negative contribution of trade within global value chains in 2014 was also revealed. During the investigated period (2000—2014), such a picture was observed only in the crisis periods, which may indicate the beginning of structural changes in the world trade.

scholarly journals Production of Structured Phosphatidylcholine with High Content of Myristic Acid by Lipase-Catalyzed Acidolysis and Interesterification

Catalysts ◽  
2018 ◽  
Vol 8 (7) ◽  
pp. 281 ◽  
Author(s):  
Anna Chojnacka ◽  
Witold Gładkowski
Keyword(s):  
Myristic Acid ◽  
Rhizomucor Miehei ◽  
Egg Yolk ◽  
Thermomyces Lanuginosus ◽  
Molar Ratio ◽  
Acyl Donor ◽  
Thermomyces Lanuginosus Lipase ◽  
Screening Experiments ◽  
Miehei Lipase ◽  
Acyl Donors

Synthesis of structured phosphatidylcholine (PC) enriched with myristic acid (MA) was conducted by acidolysis and interesterification reactions using immobilized lipases as catalysts and two acyl donors: trimyristin (TMA) isolated from ground nutmeg, and myristic acid obtained by saponification of TMA. Screening experiments indicated that the most effective biocatalyst for interesterification was Rhizomucor miehei lipase (RML), whereas for acidolysis, the most active were Thermomyces lanuginosus lipase (TLL) and RML. The effect of the molar ratio of substrates (egg-yolk PC/acyl donor), enzyme loading, and different solvent on the incorporation of MA into PC and on PC recovery was studied. The maximal incorporation of MA (44 wt%) was achieved after 48 h of RML-catalyzed interesterification in hexane using substrates molar ratio (PC/trimyristin) 1/5 and 30% enzyme load. Comparable results were obtained in toluene with 1/3 substrates molar ratio. Interesterification of PC with trimyristin resulted in significantly higher MA incorporation than acidolysis with myristic acid, particularly in the reactions catalyzed by RML.

scholarly journals Enzymatic synthesis and application of fatty acid ascorbyl esters

2013 ◽  
Vol 67 (2) ◽  
pp. 239-247 ◽  
Author(s):  
Marija Stojanovic ◽  
Milica Carevic ◽  
Mladen Mihailovic ◽  
Zorica Knezevic-Jugovic ◽  
Slobodan Petrovic ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Vitamin C ◽  
Organic Solvents ◽  
Molecular Sieves ◽  
Reaction Medium ◽  
Log P ◽  
Acyl Donor ◽  
Vinyl Esters ◽  
Ascorbyl Esters ◽  
Acyl Donors

Fatty acid ascorbyl esters are liposoluble substances that possess good antioxidative properties. These compounds could be synthesized by using various acyl donors for acylation of vitamin C in reaction catalyzed by chemical means or lipases. Enzymatic process is preferred since it is regioselective, performed under mild reaction conditions, with the obtained product being environmentally friendly. Polar organic solvents, ionic liquids, and supercritical fluids has been successfully used as a reaction medium, since commonly used solvents with high Log P values are inapplicable due to ascorbic acid high polarity. Acylation of vitamin C using fatty acids, their methyl-, ethyl-, and vinyl esters, as well as triglycerides has been performed, whereas application of the activated acyl donors enabled higher molar conversions. In each case, majority of authors reported that using excessive amount of the acyl donor had positive effect on yield of product. Furthermore, several strategies have been employed for shifting the equilibrium towards the product by water content control. These include adjusting the initial water activity by pre-equilibration of reaction mixture, enzyme preparation with water vapor of saturated salt solutions, and the removal of formed water by the addition of molecular sieves or salt hydrate pairs. The aim of this article is to provide a brief overview of the procedures described so far for the lipase-catalyzed synthesis of fatty acid ascorbyl esters with emphasis on the potential application in food, cosmetics, and pharmaceutics. Furthermore, it has been pointed out that the main obstacles for process commercialization are long reaction times, lack of adequate purification methods, and high costs of lipases. Thus, future challenges in this area are testing new catalysts, developing continuous processes for esters production, finding cheaper acyl donors and reaction mediums, as well as identifying standard procedures for purification of products which will not require consumption of large amounts of non-biocompatible organic solvents.

scholarly journals Use of isotopically labeled substrates reveals kinetic differences between human and bacterial serine palmitoyltransferase

2019 ◽  
Vol 60 (5) ◽  
pp. 953-962 ◽  
Author(s):  
Peter J. Harrison ◽  
Kenneth Gable ◽  
Niranjanakumari Somashekarappa ◽  
Van Kelly ◽  
David J. Clarke ◽  
...  
Keyword(s):  
In Vivo Studies ◽  
Serine Palmitoyltransferase ◽  
Biochemical Pathways ◽  
Catalytic Mechanisms ◽  
Catalyzed Reactions ◽  
Enzyme Catalyzed Reactions ◽  
The Impact ◽  
Sphingolipid Biosynthesis

Isotope labels are frequently used tools to track metabolites through complex biochemical pathways and to discern the mechanisms of enzyme-catalyzed reactions. Isotopically labeled l-serine is often used to monitor the activity of the first enzyme in sphingolipid biosynthesis, serine palmitoyltransferase (SPT), as well as labeling downstream cellular metabolites. Intrigued by the effect that isotope labels may be having on SPT catalysis, we characterized the impact of different l-serine isotopologues on the catalytic activity of recombinant SPT isozymes from humans and the bacterium Sphingomonas paucimobilis. Our data show that S. paucimobilis SPT activity displays a clear isotope effect with [2,3,3-D]l-serine, whereas the human SPT isoform does not. This suggests that although both human and S. paucimobilis SPT catalyze the same chemical reaction, there may well be underlying subtle differences in their catalytic mechanisms. Our results suggest that it is the activating small subunits of human SPT that play a key role in these mechanistic variations. This study also highlights that it is important to consider the type and location of isotope labels on a substrate when they are to be used in in vitro and in vivo studies.

scholarly journals Inactivation of penicillin acylase from Kluyvera citrophila by N-ethoxycarbonyl-2-ethoxy-1,2-dihydroquinoline: a case of time-dependent non-covalent enzyme inhibition

1993 ◽  
Vol 291 (3) ◽  
pp. 907-914 ◽  
Author(s):  
J Martín ◽  
J M Mancheño ◽  
R Arche
Keyword(s):  
Enzyme Assay ◽  
Ph Dependence ◽  
Penicillin Acylase ◽  
Enzyme Inactivation ◽  
Time Dependent ◽  
Penicillin G ◽  
Reversible Binding ◽  
Ph Increase ◽  
Kinetics Of ◽  
Covalent Activation

Penicillin acylase (PA) from Kluyvera citrophila was inhibited by N-ethoxycarbonyl-2-ethoxy-1,2-dihydroquinoline (EEDQ), a specific carboxy-group-reactive reagent. Enzyme activity progressively decreased to a residual value depending on EEDQ concentration. Neither enzymic nor non-enzymic decomposition of EEDQ is concomitant with PA inactivation. Moreover, enzyme re-activation is achieved by chromatographic removal of EEDQ, pH increase or displacement of the reagent with penicillin G. It was then concluded that PA inactivation is due to an equilibrium reaction. The kinetics of enzyme inactivation was analysed by fitting data to theoretical equations derived in accordance with this mechanism. Corrections for re-activation during the enzyme assay were a necessary introduction. The pH-dependence of the rate constant for EEDQ hydrolysis either alone or in the presence of enzyme was studied by u.v. spectroscopy. It turned out to be coincident with the pH-dependence of the forward and reverse rate constants for the inactivation process. It is suggested that previous protonation of the EEDQ molecule is required for these reactions to occur. The thermodynamic values associated with the overall reaction showed little change. Finally it is proposed that the inactivation of PA by EEDQ proceeds through a two-step reaction. The initial and rapid reversible binding is followed by a slow, time-dependent, non-covalent, reversible inactivating step. The expected behaviour in the case of enzyme modification by covalent activation of carboxy residues is also reviewed.

The influence of pH on the thermal stability of penicillin acylase from Alcaligenes faecalis

2010 ◽  
Vol 65 (3) ◽  
pp. 135-138
Author(s):  
A. V. Stepashkina ◽  
A. S. Yasnaya ◽  
A. I. Berezin ◽  
V. I. Tishkov
Keyword(s):  
Thermal Stability ◽  
Alcaligenes Faecalis ◽  
Penicillin Acylase ◽  
Influence Of Ph ◽  
Thermal Stability Of

scholarly journals Processing and functional display of the 86 kDa heterodimeric penicillin G acylase on the surface of phage fd

1999 ◽  
Vol 342 (2) ◽  
pp. 415-422 ◽  
Author(s):  
Raymond M. D. VERHAERT ◽  
Jan VAN DUIN ◽  
Wim J. QUAX
Keyword(s):  
Coat Protein ◽  
Signal Sequence ◽  
Protein A ◽  
Alcaligenes Faecalis ◽  
Penicillin Acylase ◽  
Penicillin G Acylase ◽  
Penicillin G ◽  
Β Subunit ◽  
Extracellular Medium ◽  
Α Subunit

The large heterodimeric penicillin G acylase from Alcaligenes faecalis was displayed on the surface of phage fd. We fused the coding sequence (α subunit-internal peptide-β subunit) to the gene of a phage coat protein. A modified g3p signal sequence was used to direct the polypeptide to the periplasm. Here we show that a heterodimeric enzyme can be expressed as a fusion protein that matures to an active biocatalyst connected to the coat protein of phage fd, resulting in a phage to which the β-subunit is covalently linked and the α-subunit is non-covalently attached. The enzyme can be displayed either fused to the minor coat protein g3p or fused to the major coat protein g8p. In both cases the penicillin G acylase on the phage has the same Michaelis constant as its freely soluble counterpart, indicating a proper folding and catalytic activity of the displayed enzyme. The display of the heterodimer on phage not only allows its further use in protein engineering but also offers the possibility of applying this technology for the excretion of the enzyme into the extracellular medium, facilitating purification of the protein. With the example of penicillin acylase the upper limit for a protein to become functionally displayed by phage fd has been further explored. Polyvalent display was not observed despite the use of genetic constructs designed for this aim. These results are discussed in relation to the pore size being formed by the g4p multimer.

Relative suitability of 1-palmitoyl and 1-stearoyl homologues of 1-acyl-sn-glycerylphosphorylcholine and different acyl donors for phosphatidylcholine synthesis via acyl-CoA:1-acyl-sn-glycero-3-phosphorylcholine acyltransferase in rat lung microsomes

1980 ◽  
Vol 58 (5) ◽  
pp. 434-439 ◽  
Author(s):  
B. J. Holub ◽  
J. Plekarski ◽  
F. Possmayer
Keyword(s):  
Fatty Acids ◽  
The Other ◽  
Acyl Donor ◽  
Rat Lung ◽  
Acceptor Reaction ◽  
Acyl Acceptor ◽  
Dipalmitoyl Phosphatidylcholine ◽  
Acyl Donors ◽  
Phosphatidylcholine Synthesis ◽  
Assay Conditions

The relative suitability of the 1-palmitoyl and 1-stearoyl homologues of 1-acyl-sn-glyceryl-phosphorylcholine and different acyl donors were tested as substrates for phosphatidylcholine synthesis via the acyl-CoA:1-acyl-sn-glycero-3-phosphorylcholine acyltransferase in rat lung microsomes. The acyl acceptor was an almost equi-molar mixture of the [3H]palmitoyl plus [14C]stearoyl species of 1-acyl-sn-glycero-3-phosphorylcholine with palmitoyl-, stearoyl-, oleoyl-, linoleoyl-, or arachidonoyl-CoA serving as the acyl donor. At all concentrations of acyl acceptor, reaction velocities with 20:4-CoA ≥ 18:2-CoA > 18:1-CoA > 16:0-CoA > 18:0-CoA. Furthermore, the acyltransferase selectively utilized the 1-palmitoyl over the 1-stearoyl species of 1-acylglycerylphosphorylcholine by 4.2- to 5.7-fold under optimal assay conditions with the various acyl-CoA thiolesters. However, the degree of preference exhibited for the 1-palmitoyl-sn-glycero-3-phosphorylcholine, as acyl acceptor, versus the 1-stearoyl homologue with palmitoyl-CoA as the acyl donor was not significantly different from that obtained with the other acyl-CoA derivatives. Thus, the specificity of the acyl-CoA:1-acyl-sn-glycero-3-phosphorylcholine acyltransferase indicates an ability of this enzyme to produce dipalmitoyl phosphatidylcholine but it cannot independently explain the predominance of dipalmitoyl phosphatidylcholine in lung or the tendency of stearate at the 1-position to associate with fatty acids of increasing unsaturation at the 2-position.

Efficient Enzymatic Amine Resolution at High Substrate Input Using Diethyl Malonate as an Acyl Donor of Low Hazard Potential

2012 ◽  
Vol 67 (10) ◽  
pp. 1123-1126 ◽  
Author(s):  
Sabine Simon ◽  
Steffen Oßwald ◽  
Jürgen Roos ◽  
Harald Gröger
Keyword(s):  
Organic Solvent ◽  
Diethyl Malonate ◽  
Attractive Alternative ◽  
Acyl Donor ◽  
Enzymatic Process ◽  
Solvent Selection ◽  
High Substrate ◽  
Hazard Potential ◽  
Highly Efficient ◽  
Acyl Donors

Diethyl malonate turned out to be both a “green” and highly efficient acyl donor in the lipase-catalyzed resolution of amines, thus representing an attractive alternative to currently applied acyl donors. By means of this acyl donor a highly efficient enzymatic process for the resolution of amines, running at high substrate input of up to 200 g/L in an organic solvent classified as “usable” according to the Pfizer Solvent Selection Guide, is presented.

scholarly journals Development of dynamic kinetic resolution on large scale for (±)-1-phenylethylamine

2010 ◽  
Vol 6 ◽  
pp. 823-829 ◽  
Author(s):  
Lisa K Thalén ◽  
Jan-E Bäckvall
Keyword(s):  
Good Yield ◽  
Large Scale ◽  
Kinetic Resolution ◽  
Catalyst Loading ◽  
Acyl Donor ◽  
Dynamic Kinetic Resolution ◽  
Reaction Parameters ◽  
Ru Catalyst ◽  
Isopropyl Acetate ◽  
Acyl Donors

Candida antarctica lipase B (CALB) and racemization catalyst 4 were combined in the dynamic kinetic resolution (DKR) of (±)-1-phenylethylamine (1). Several reaction parameters have been investigated to modify the method for application on multigram scale. A comparison of isopropyl acetate and alkyl methoxyacetates as acyl donors was carried out. It was found that lower catalyst loadings could be used to obtain (R)-2-methoxy-N-(1-phenylethyl)acetamide (3) in good yield and high ee when alkyl methoxyacetates were used as acyl donors compared to when isopropyl acetate was used as the acyl donor. The catalyst loading could be decreased to 1.25 mol % Ru-catalyst 4 and 10 mg CALB per mmol 1 when alkyl methoxyacetates were used as the acyl donor.

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