1
|
Kuchaříková H, Dobrovolná P, Lochmanová G, Zdráhal Z. Trimethylacetic Anhydride-Based Derivatization Facilitates Quantification of Histone Marks at the MS1 Level. Mol Cell Proteomics 2021; 20:100114. [PMID: 34129942 PMCID: PMC8283018 DOI: 10.1016/j.mcpro.2021.100114] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 05/11/2021] [Accepted: 06/08/2021] [Indexed: 12/30/2022] Open
Abstract
Histone post-translational modifications (hPTMs) are epigenetic marks that strongly affect numerous processes, including cell cycling and protein interactions. They have been studied by both antibody- and MS-based methods for years, but the analyses are still challenging, mainly because of the diversity of histones and their modifications arising from high contents of reactive amine groups in their amino acid sequences. Here, we introduce use of trimethylacetic anhydride (TMA) as a new reagent for efficient histone derivatization, which is a requirement for bottom-up proteomic hPTM analysis. TMA can derivatize unmodified amine groups of lysine residues and amine groups generated at peptide N-termini by trypsin digestion. The derivatization is facilitated by microwave irradiation, which also reduces incubation times to minutes. We demonstrate that histone derivatization with TMA reliably provides high yields of fully derivatized peptides and thus is an effective alternative to conventional methods. TMA afforded more than 98% and 99% labeling efficiencies for histones H4 and H3, respectively, thereby enabling accurate quantification of peptide forms. Trimethylacetylation substantially improves chromatographic separation of peptide forms, which is essential for direct quantification based on signals extracted from MS1 data. For this purpose, software widely applied by the proteomics community can be used without additional computational development. Thorough comparison with widely applied propionylation highlights the advantages of TMA-based histone derivatization for monitoring hPTMs in biological samples.
Collapse
Affiliation(s)
- Hana Kuchaříková
- Central European Institute of Technology, Masaryk University, Brno, Czech Republic; Faculty of Science, Masaryk University, Brno, Czech Republic
| | - Pavlína Dobrovolná
- Central European Institute of Technology, Masaryk University, Brno, Czech Republic
| | - Gabriela Lochmanová
- Central European Institute of Technology, Masaryk University, Brno, Czech Republic.
| | - Zbyněk Zdráhal
- Central European Institute of Technology, Masaryk University, Brno, Czech Republic; Faculty of Science, Masaryk University, Brno, Czech Republic.
| |
Collapse
|
2
|
Zięba T, Wilczak A, Kobryń J, Musiał W, Kapelko-Żeberska M, Gryszkin A, Meisel M. The Annealing of Acetylated Potato Starch with Various Substitution Degrees. Molecules 2021; 26:2096. [PMID: 33917516 PMCID: PMC8038830 DOI: 10.3390/molecules26072096] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Revised: 03/26/2021] [Accepted: 04/05/2021] [Indexed: 11/17/2022] Open
Abstract
This study aimed to determine the effect of "annealing" acetylated potato starch with a homogenous granule size and various degrees of substitution on the thermal pasting characteristics (DSC), resistance to amylases, rheology of the prepared pastes, swelling power and dynamics of drug release. A fraction of large granules was separated from native starch with the sedimentation method and acetylated with various doses of acetic anhydride (6.5, 13.0 or 26.0 26 cm3/100 g starch). The starch acetates were then annealed at slightly lower temperatures than their pasting temperatures. The annealing process caused an almost twofold increase in the resistance to amylolysis and a threefold increase in the swelling power of the modified starch preparations. The heat of phase transition decreased almost two times and the range of starch pasting temperatures over two times, but the pasting temperature itself increased by ca. 10 °C. The 40 g/100 g addition of the modified starch preparation decreased the rate of drug release from a hydrogel by ca. one-fourth compared to the control sample.
Collapse
Affiliation(s)
- Tomasz Zięba
- Department of Food Storage and Technology, Faculty of Biotechnology and Food Science, Wroclaw University of Environmental and Life Sciences, Chełmońskiego 37, 51-630 Wrocław, Poland; (T.Z.); (A.G.); (M.M.)
| | - Aleksandra Wilczak
- Department of Physico-Chemistry of Microorganisms, University of Wroclaw, Przybyszewskiego 63-77, 51-148 Wrocław, Poland;
| | - Justyna Kobryń
- Department and Chair of Physical Chemistry and Biophysics, Wrocław Medical University, Borowska 211A, 50-556 Wrocław, Poland; (J.K.); (W.M.)
| | - Witold Musiał
- Department and Chair of Physical Chemistry and Biophysics, Wrocław Medical University, Borowska 211A, 50-556 Wrocław, Poland; (J.K.); (W.M.)
| | - Małgorzata Kapelko-Żeberska
- Department of Food Storage and Technology, Faculty of Biotechnology and Food Science, Wroclaw University of Environmental and Life Sciences, Chełmońskiego 37, 51-630 Wrocław, Poland; (T.Z.); (A.G.); (M.M.)
| | - Artur Gryszkin
- Department of Food Storage and Technology, Faculty of Biotechnology and Food Science, Wroclaw University of Environmental and Life Sciences, Chełmońskiego 37, 51-630 Wrocław, Poland; (T.Z.); (A.G.); (M.M.)
| | - Marta Meisel
- Department of Food Storage and Technology, Faculty of Biotechnology and Food Science, Wroclaw University of Environmental and Life Sciences, Chełmońskiego 37, 51-630 Wrocław, Poland; (T.Z.); (A.G.); (M.M.)
| |
Collapse
|
3
|
Elvas-Leitão R, Martins F, Borbinha L, Marranita C, Martins A, Nunes N. Probing Substrate/Catalyst Effects Using QSPR Analysis on Friedel-Crafts Acylation Reactions over Hierarchical BEA Zeolites. Molecules 2020; 25:molecules25235682. [PMID: 33276487 PMCID: PMC7730844 DOI: 10.3390/molecules25235682] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/15/2020] [Revised: 11/29/2020] [Accepted: 11/30/2020] [Indexed: 11/16/2022]
Abstract
Attempts to optimize heterogeneous catalysis often lack quantitative comparative analysis. The use of kinetic modelling leads to rate (k) and relative sorption equilibrium constants (K), which can be further rationalized using Quantitative Structure-Property Relationships (QSPR) based on Multiple Linear Regressions (MLR). Friedel-Crafts acylation using commercial and hierarchical BEA zeolites as heterogeneous catalysts, acetic anhydride as the acylating agent, and a set of seven substrates with different sizes and chemical functionalities were herein studied. Catalytic results were correlated with the physicochemical properties of substrates and catalysts. From this analysis, a robust set of equations was obtained allowing inferences about the dominant factors governing the processes. Not entirely surprising, the rate and sorption equilibrium constants were found to be explained in part by common factors but of opposite signs: higher and stronger adsorption forces increase reaction rates, but they also make the zeolite active sites less accessible to new reactant molecules. The most relevant parameters are related to the substrates’ molecular size, which can be associated with different reaction steps, namely accessibility to micropores, diffusion capacity, and polarizability of molecules. The relatively large set of substrates used here reinforces previous findings and brings further insights into the factors that hamper/speed up Friedel-Crafts reactions in heterogeneous media.
Collapse
Affiliation(s)
- Ruben Elvas-Leitão
- Área Departamental de Engenharia Química, Instituto Superior de Engenharia de Lisboa, IPL, R. Conselheiro Emídio Navarro, 1959-007 Lisboa, Portugal;
- Centro de Química Estrutural (CQE), Faculdade de Ciências, Universidade de Lisboa, 1749-016 Lisboa, Portugal; (F.M.); (L.B.)
- Correspondence: (R.E.-L.); (N.N.); Tel.: +351-218317000 (R.E.-L. & N.N.)
| | - Filomena Martins
- Centro de Química Estrutural (CQE), Faculdade de Ciências, Universidade de Lisboa, 1749-016 Lisboa, Portugal; (F.M.); (L.B.)
| | - Leonor Borbinha
- Centro de Química Estrutural (CQE), Faculdade de Ciências, Universidade de Lisboa, 1749-016 Lisboa, Portugal; (F.M.); (L.B.)
| | - Catarina Marranita
- Escola Profissional de Setúbal, R. Professor Borges de Macedo, n° 1, 2910-001 Setúbal, Portugal;
| | - Angela Martins
- Área Departamental de Engenharia Química, Instituto Superior de Engenharia de Lisboa, IPL, R. Conselheiro Emídio Navarro, 1959-007 Lisboa, Portugal;
- Centro de Química Estrutural (CQE), Faculdade de Ciências, Universidade de Lisboa, 1749-016 Lisboa, Portugal; (F.M.); (L.B.)
| | - Nelson Nunes
- Área Departamental de Engenharia Química, Instituto Superior de Engenharia de Lisboa, IPL, R. Conselheiro Emídio Navarro, 1959-007 Lisboa, Portugal;
- Centro de Química Estrutural (CQE), Faculdade de Ciências, Universidade de Lisboa, 1749-016 Lisboa, Portugal; (F.M.); (L.B.)
- Correspondence: (R.E.-L.); (N.N.); Tel.: +351-218317000 (R.E.-L. & N.N.)
| |
Collapse
|
4
|
Tachibana A, Yasuma D, Takahashi R, Tanabe T. Chitin degradation enzyme-responsive system for controlled release of fibroblast growth factor-2. J Biosci Bioeng 2019; 129:116-120. [PMID: 31492610 DOI: 10.1016/j.jbiosc.2019.07.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Revised: 06/07/2019] [Accepted: 07/19/2019] [Indexed: 11/19/2022]
Abstract
Chitin is widely found in fungal cell walls and arthropod exoskeletons, and is used as a biomedical material. However, chitin is not water-soluble, restricting its use for controlled release materials. We found that water-soluble chitosan can be acetylated to produce a chitin equivalent, or chitin gel. Chitin gel, produced by mixing chitosan solution with acetic anhydride, can be degraded by lysozyme and fetal bovine serum, so could provide an ideal means for controlled release in biological systems. We tested a combination of chitin gel with a chitin binding domain (CBD) fusion protein as a controlled release system regulated by chitin degradation. A fusion protein consisting of fibroblast growth factor 2 (FGF-2) fused to CBD bound the chitin gel, and was released time-dependently rather than as an initial burst during lysozyme degradation, suggesting that this system could provide a means for controlled drug release in biological systems. Contrastingly, the trinitrophenyl residue (TNP-X) covalently bound to chitin gel, and was released by lysozyme degradation with an initial burst. If release of CBD-FGF-2 were simply dependent on lysozyme degradation of the chitin gel, the release behavior of CBD-FGF-2 would be similar to that of TNP-X, with an initial burst. Therefore, we propose that CBD-FGF-2 repeats the cycle of binding, release, and re-binding to the chitin gel during degradation. This system allows for a time-dependent, controlled release of CBD-FGF-2 without an initial burst.
Collapse
Affiliation(s)
- Akira Tachibana
- Department of Bioengineering, Graduate School of Engineering, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan.
| | - Dai Yasuma
- Department of Bioengineering, Graduate School of Engineering, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan
| | - Ryo Takahashi
- Department of Bioengineering, Graduate School of Engineering, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan
| | - Toshizumi Tanabe
- Department of Bioengineering, Graduate School of Engineering, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan
| |
Collapse
|
5
|
Casas-Hinestroza JL, Maldonado M. Conformational Aspects of the O-acetylation of C-tetra(phenyl)calixpyrogallol[4]arene. Molecules 2018; 23:molecules23051225. [PMID: 29783780 PMCID: PMC6100403 DOI: 10.3390/molecules23051225] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2018] [Revised: 05/15/2018] [Accepted: 05/17/2018] [Indexed: 11/16/2022] Open
Abstract
Reaction between pyrogallol and benzaldehyde results in a conformational mixture of C-tetra(phenyl)pyrogallol[4]arene (crown and chair). The conformer mixture was separated using crystallization procedures and the structures were determined using FTIR, 1H-NMR, and 13C-NMR. O-acetylation of C-tetra(phenyl)pyrogallol[4]arene (chair) with acetic anhydride, in pyridine results in the formation of dodecaacetyl-tetra(phenyl)pyrogallol[4]arene. The structure was determined using 1H-NMR and 13C-NMR finding that the product maintains the conformation of the starting conformer. On the other hand, the O-acetylation reaction of C-tetra(phenyl)pirogallol[4]arene (crown) under same conditions proceeded efficiently, and its structure was determined using 1H-NMR and 13C-NMR. Dynamic 1H-NMR of acetylated pyrogallolarene was studied by means of variable temperature in DMSO-d6 solution, and it revealed that two conformers are formed in the solution. Boat conformations for acetylated pyrogallolarene showed a slow interconversion at room temperature.
Collapse
Affiliation(s)
- José Luis Casas-Hinestroza
- Departamento de Química, Facultad de Ciencias, Universidad Nacional de Colombia-sede Bogotá, Carrera 30 # 45-03, Bogotá 111321, Columbia.
| | - Mauricio Maldonado
- Departamento de Química, Facultad de Ciencias, Universidad Nacional de Colombia-sede Bogotá, Carrera 30 # 45-03, Bogotá 111321, Columbia.
| |
Collapse
|
6
|
Neves AR, Correia-da-Silva M, Silva PMA, Ribeiro D, Sousa E, Bousbaa H, Pinto M. Synthesis of New Glycosylated Flavonoids with Inhibitory Activity on Cell Growth. Molecules 2018; 23:molecules23051093. [PMID: 29734739 PMCID: PMC6102538 DOI: 10.3390/molecules23051093] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Revised: 05/02/2018] [Accepted: 05/02/2018] [Indexed: 01/22/2023] Open
Abstract
Natural flavonoids and xanthone glycosides display several biological activities, with the glycoside moiety playing an important role in the mechanism of action of these metabolites. Herein, to give further insights into the inhibitory activity on cell growth of these classes of compounds, the synthesis of four flavonoids (5, 6, 9, and 10) and one xanthone (7) containing one or more acetoglycoside moieties was carried out. Acetyl groups were introduced using acetic anhydride and microwave irradiation. The introduction of one or two acetoglycoside moieties in the framework of 3,7-dihydroxyflavone (4) was performed using two synthetic methods: the Michael reaction and the Koenigs-Knorr reaction. The in vitro cell growth inhibitory activity of compounds 5, 6, 7, 9, and 10 was investigated in six human tumor cell lines: A375-C5 (malignant melanoma IL-1 insensitive), MCF-7 (breast adenocarcinoma), NCI-H460 (non-small cell lung cancer), U251 (glioblastoma astrocytoma), U373 (glioblastoma astrocytoma), and U87MG (glioblastoma astrocytoma). The new flavonoid 3-hydroxy-7-(2,3,4,6-tetra-O-acetyl-β-glucopyranosyl) flavone (10) was the most potent compound in all tumor cell lines tested, with GI50 values < 8 μM and a notable degree of selectivity for cancer cells.
Collapse
Affiliation(s)
- Ana R Neves
- Laboratory of Organic and Pharmaceutical Chemistry, Department of Chemical Sciences, Faculty of Pharmacy, University of Porto, Rua Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal.
- Interdisciplinary Centre of Marine and Environmental Research (CIIMAR), University of Porto, Terminal de Cruzeiros do Porto de Leixões, Avenida General Norton de Matos, S/N 4450-208 Matosinhos, Portugal.
| | - Marta Correia-da-Silva
- Laboratory of Organic and Pharmaceutical Chemistry, Department of Chemical Sciences, Faculty of Pharmacy, University of Porto, Rua Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal.
- Interdisciplinary Centre of Marine and Environmental Research (CIIMAR), University of Porto, Terminal de Cruzeiros do Porto de Leixões, Avenida General Norton de Matos, S/N 4450-208 Matosinhos, Portugal.
| | - Patrícia M A Silva
- CESPU, Institute of Research and Advanced Training in Health Sciences and Technologies (IINFACTS), Rua Central de Gandra, 1317, 4585-116 Gandra, Portugal.
| | - Diana Ribeiro
- CESPU, Institute of Research and Advanced Training in Health Sciences and Technologies (IINFACTS), Rua Central de Gandra, 1317, 4585-116 Gandra, Portugal.
| | - Emília Sousa
- Laboratory of Organic and Pharmaceutical Chemistry, Department of Chemical Sciences, Faculty of Pharmacy, University of Porto, Rua Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal.
- Interdisciplinary Centre of Marine and Environmental Research (CIIMAR), University of Porto, Terminal de Cruzeiros do Porto de Leixões, Avenida General Norton de Matos, S/N 4450-208 Matosinhos, Portugal.
| | - Hassan Bousbaa
- Interdisciplinary Centre of Marine and Environmental Research (CIIMAR), University of Porto, Terminal de Cruzeiros do Porto de Leixões, Avenida General Norton de Matos, S/N 4450-208 Matosinhos, Portugal.
- CESPU, Institute of Research and Advanced Training in Health Sciences and Technologies (IINFACTS), Rua Central de Gandra, 1317, 4585-116 Gandra, Portugal.
| | - Madalena Pinto
- Laboratory of Organic and Pharmaceutical Chemistry, Department of Chemical Sciences, Faculty of Pharmacy, University of Porto, Rua Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal.
- Interdisciplinary Centre of Marine and Environmental Research (CIIMAR), University of Porto, Terminal de Cruzeiros do Porto de Leixões, Avenida General Norton de Matos, S/N 4450-208 Matosinhos, Portugal.
| |
Collapse
|
7
|
Zhang P, Ling CC. A mild acetolysis procedure for the regioselective removal of isopropylidene in di-O-isopropylidene-protected pyranoside systems. Carbohydr Res 2017; 445:7-13. [PMID: 28376356 DOI: 10.1016/j.carres.2017.03.021] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Revised: 03/27/2017] [Accepted: 03/28/2017] [Indexed: 11/19/2022]
Abstract
A mild acetolysis method for the regioselective removal of isopropylidene group from di-O-isopropylidene-protected hexopyranosides is reported. O-Isopropylidene-protected intermediates play an important role in carbohydrate chemistry, as they are often found in commercially available furanosyl and pyranosyl materials, and some of them contain more than one O-isopropylidene groups. Methods that permit regioselective removal of O-isopropylidene groups are extremely valuable, as the number of steps in the total synthesis of complex oligosaccharides could be significantly decreased. Here we report that trifluoroacetic acid (TFA)/acetic anhydride (Ac2O) can be used to regioselectively convert one of the two O-isopropylidene groups to vicinal di-O-acetates in the di-O-isopropylidene-protected galacto- and fructo-pyranosyl systems, and the reagent is compatible with some common functionalities such as sulfonate esters, bromide, azide etc.
Collapse
Affiliation(s)
- Pengfei Zhang
- Alberta Glycomics Centre, Department of Chemistry, University of Calgary, Calgary, Alberta, T2N 1N4, Canada
| | - Chang-Chun Ling
- Alberta Glycomics Centre, Department of Chemistry, University of Calgary, Calgary, Alberta, T2N 1N4, Canada.
| |
Collapse
|
8
|
Yang F, Oyeyinka SA, Ma Y. Novel Synthesis of Phytosterol Ester from Soybean Sterol and Acetic Anhydride. J Food Sci 2016; 81:C1629-35. [PMID: 27240315 DOI: 10.1111/1750-3841.13354] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Revised: 04/28/2016] [Accepted: 05/01/2016] [Indexed: 11/30/2022]
Abstract
Phytosterols are important bioactive compounds which have several health benefits including reduction of serum cholesterol and preventing cardiovascular diseases. The most widely used method in the synthesis of its ester analogous form is the use of catalysts and solvents. These methods have been found to present some safety and health concern. In this paper, an alternative method of synthesizing phytosterol ester from soybean sterol and acetic anhydride was investigated. Process parameters such as mole ratio, temperature and time were optimized. The structure and physicochemical properties of phytosterol acetic ester were analyzed. By the use of gas chromatography, the mole ratio of soybean sterol and acetic anhydride needed for optimum esterification rate of 99.4% was 1:1 at 135 °C for 1.5 h. FTIR spectra confirmed the formation of phytosterol ester with strong absorption peaks at 1732 and 1250 cm(-1) , which corresponds to the stretching vibration of C=O and C-O-C, respectively. These peaks could be attributed to the formation of ester links which resulted from the reaction between the hydroxyl group of soybean sterol and the carbonyl group of acetic anhydride. This paper provides a better alternative to the synthesis of phytosterol ester without catalyst and solvent residues, which may have potential application in the food, health-care food, and pharmaceutical industries.
Collapse
Affiliation(s)
- Fuming Yang
- School of Chemical Engineering, Harbin Inst. of Technology, Harbin, 150090, China
| | - Samson A Oyeyinka
- School of Chemical Engineering, Harbin Inst. of Technology, Harbin, 150090, China
- Dept. of Home Economics and Food Science, Univ. of Ilorin, PMB 1515, Ilorin, Nigeria
| | - Ying Ma
- School of Chemical Engineering, Harbin Inst. of Technology, Harbin, 150090, China
| |
Collapse
|
9
|
Aisha Mahmood Abdulkareem AT, Selvin R. Enhanced Activity of Nanocrystalline Beta Zeolite for Acylation of Veratrole with Acetic Anhydride. J Nanosci Nanotechnol 2016; 16:4247-4251. [PMID: 27451793 DOI: 10.1166/jnn.2016.11613] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Friedel-Craft acylation of veratrole using homogeneous acid catalysts such as AlCl3, FeCl3, ZnCl2, and HF etc. produces acetoveratrone, (3',4'-dimethoxyacetophenone), which is the intermediate for synthesis of papavarine alkaloids. The problems associated with these homogeneous catalysts can be overcome by using heterogeneous solid catalysts. Since acetoveratrone is a larger molecule, large pore Beta zeolites with smaller particle sizes are beneficial for the liquid-phase acylation of veratrole, for easy diffusion of reactants and products. The present study aims in the acylation of veratrole with acetic anhydride using nanocrystalline Beta Zeolite catalyst. A systematic investigation of the effects of various reaction parameters was done. The catalysts were characterized for their structural features by using XRD, TEM and DLS analyses. The catalytic activity of nanocrystalline Beta zeolite was compared with commercial Beta zeolite for the acylation and was found that nanocrystalline Beta zeolite possessed superior activity.
Collapse
|
10
|
Dodson JR, Leite TDCM, Pontes NS, Peres Pinto B, Mota CJA. Green acetylation of solketal and glycerol formal by heterogeneous acid catalysts to form a biodiesel fuel additive. ChemSusChem 2014; 7:2728-2734. [PMID: 25045049 DOI: 10.1002/cssc.201402070] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2014] [Revised: 05/04/2014] [Indexed: 06/03/2023]
Abstract
A glut of glycerol has formed from the increased production of biodiesel, with the potential to integrate the supply chain by using glycerol additives to improve biodiesel properties. Acetylated acetals show interesting cold flow and viscosity effects. Herein, a solventless heterogeneously catalyzed process for the acetylation of both solketal and glycerol formal to new products is demonstrated. The process is optimized by studying the effect of acetylating reagent (acetic acid and acetic anhydride), reagent molar ratios, and a variety of commercial solid acid catalysts (Amberlyst-15, zeolite Beta, K-10 Montmorillonite, and niobium phosphate) on the conversion and selectivities. High conversions (72-95%) and selectivities (86-99%) to the desired products results from using acetic anhydride as the acetylation reagent and a 1:1 molar ratio with all catalysts. Overall, there is a complex interplay between the solid catalyst, reagent ratio, and acetylating agent on the conversion, selectivities, and byproducts formed. The variations are discussed and explained in terms of reactivity, thermodynamics, and reaction mechanisms. An alternative and efficient approach to the formation of 100% triacetin involves the ring-opening, acid-catalyzed acetylation from solketal or glycerol formal with excesses of acetic anhydride.
Collapse
Affiliation(s)
- Jennifer R Dodson
- Institute of Chemistry, Federal University of Rio de Janeiro, Cidade Universitária-Rio de Janeiro, 21941-909 (Brazil)
| | | | | | | | | |
Collapse
|
11
|
Li K, Liu S, Tan Y, Chao N, Tian X, Qi L, Powell WA, Jiang X, Gai Y. Optimized GC-MS method to simultaneously quantify acetylated aldose, ketose, and alditol for plant tissues based on derivatization in a methyl sulfoxide/1-methylimidazole system. J Agric Food Chem 2013; 61:4011-8. [PMID: 23541076 DOI: 10.1021/jf3053862] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
The isomers of monosaccharide always produce multiple chromatographic peaks as volatile derivatives during gas chromatography, which may result in the overlapping of different sugar peaks. Whereas reduction and oximation of sugar carbonyl groups for GC analysis do eliminate many isomer derivatives, the approaches create new problems. One ketose can yield two peaks by oximation, and different aldoses and ketoses can yield the same alditol upon reduction, leading to the inability to detect some important monosaccharides. This paper reports an optimal method that yields a single peak per sugar by acetylation directly. By using a methyl sulfoxide (Me2SO)/1-methylimidazole (1-MeIm) system, the carbohydrates in acetic anhydride (Ac2O) esterification reactions were solubilized, and the oxidation that normally occurs was inhibited. The results demonstrate that acetylated derivatives of 23 saccharides had unique peaks, which indicates aldose, ketose, and alditol can be determined simultaneously by GC-MS.
Collapse
Affiliation(s)
- Ke Li
- College of Biological Sciences and Biotechnology, Beijing Forestry University , Beijing 100083, People's Republic of China
| | | | | | | | | | | | | | | | | |
Collapse
|
12
|
de Oliveira CS, Lira BF, dos Santos Falcão-Silva V, Siqueira-Junior JP, Barbosa-Filho JM, de Athayde-Filho PF. Synthesis, molecular properties prediction, and anti-staphylococcal activity of N-acylhydrazones and new 1,3,4-oxadiazole derivatives. Molecules 2012; 17:5095-107. [PMID: 22555298 PMCID: PMC6268585 DOI: 10.3390/molecules17055095] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2012] [Revised: 04/18/2012] [Accepted: 04/19/2012] [Indexed: 11/16/2022] Open
Abstract
Five new 1-(2-(5-nitrofuran-2-yl)-5-(aryl)-1,3,4-oxadiazol-3-(2H)-yl) ethanone compounds 5a-e were synthesized by cyclization of N-acylhydrazones 4a-e with acetic anhydride under reflux conditions. Their structures were fully characterized by IR, ¹H-NMR, and ¹³C-NMR. Furthermore, evaluations of the antibacterial activity of the 1,3,4-oxadiazoles 5a-e and N-acylhydrazones 4a-e showed strong activity against several strains of Staphylococcus aureus, with MICs between 4 μg/mL to 32 μg/mL. In silico studies of the parameters of Lipinski's Rule of Five, as well as the topological polar surface area (TPSA), absorption percentage (% ABS), drug likeness and drug score indicate that these compounds, especially 4a and 5d, have potential to be new drug candidates.
Collapse
Affiliation(s)
- Cledualdo Soares de Oliveira
- Department of Chemistry, Federal University of Paraiba, João Pessoa, PB 58059-900, Brazil; E-Mails: (C.S.O.); (B.F.L.)
| | - Bruno Freitas Lira
- Department of Chemistry, Federal University of Paraiba, João Pessoa, PB 58059-900, Brazil; E-Mails: (C.S.O.); (B.F.L.)
| | - Vivyanne dos Santos Falcão-Silva
- Department of Molecular Biology, Federal University of Paraíba, João Pessoa, PB 58059-900, Brazil; E-Mails: (V.S.F.-S.); (J.P.S.-J.)
| | - Jose Pinto Siqueira-Junior
- Department of Molecular Biology, Federal University of Paraíba, João Pessoa, PB 58059-900, Brazil; E-Mails: (V.S.F.-S.); (J.P.S.-J.)
| | - Jose Maria Barbosa-Filho
- Laboratory of Pharmaceutical Technology, Federal University of Paraíba, João Pessoa, PB 58051-900, Brazil; E-Mail:
| | | |
Collapse
|
13
|
Lee SJ, Hong GY, Jeong YI, Kang MS, Oh JS, Song CE, Lee HC. Paclitaxel-incorporated nanoparticles of hydrophobized polysaccharide and their antitumor activity. Int J Pharm 2012; 433:121-8. [PMID: 22561793 DOI: 10.1016/j.ijpharm.2012.04.048] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2012] [Revised: 04/10/2012] [Accepted: 04/17/2012] [Indexed: 12/13/2022]
Abstract
The aim of this study was to characterize paclitaxel-incorporated polysaccharide nanoparticles and evaluate their antitumor activity in vitro and in vivo. Pullulan was hydrophobically modified using acetic anhydride to make the paclitaxel-incorporated nanoparticles. Pullulan acetate (PA) was used to encapsulate paclitaxel using the nanoprecipitation method. The particles had spherical shapes under electron microscopy with sizes <100 nm. The sizes of paclitaxel-incorporated nanoparticles increased to >100 nm, and higher drug feeding induced higher particle size and drug content. Initial drug burst release was observed until 2 days and then the drug was continuously released over 1 week. Intrinsic cytotoxicity of empty PA nanoparticles was tested with RAW264.7 macrophage cells for biocompatibilty. The viability of RAW264.7 cells was >93% at all concentrations of empty PA nanoparticles, indicating that the PA nanoparticles are not acutely cytotoxic to normal human cells. The nanoparticles showed lower antitumor activity in vitro against HCT116 human colon carcinoma cells than that of paclitaxel itself, indicating the sustained release properties of nanoparticles. An in vivo study using HCT116 human colon carcinoma-bearing mice showed that paclitaxel-incorporated PA nanoparticles reduced tumor growth more than that of paclitaxel itself. These results indicate that PA paclitaxel-incorporated nanoparticles are a promising candidate for antitumor drug delivery.
Collapse
Affiliation(s)
- Sang Joon Lee
- Department of Biomedical Sciences, Chonnam National University Medical School, Gwangju 501-746, Republic of Korea
| | | | | | | | | | | | | |
Collapse
|
14
|
López Y, Rodríguez L, del Río RE, Farfán N, Morzycki JW, Santillan R. Regioselective cleavage of 22-oxo-23-spiroketals. Novel cholestanic frameworks with pyranone and cyclopentenone E rings on the side chain. Steroids 2012; 77:534-41. [PMID: 22333396 DOI: 10.1016/j.steroids.2012.01.018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2011] [Revised: 01/25/2012] [Accepted: 01/27/2012] [Indexed: 10/14/2022]
Abstract
The regioselective opening of the F ring of 22-oxo-23-spiroketals using a saturated solution of HCl in acetic anhydride yielded novel cholestanic frameworks with pyranone or cyclopentenone E rings. The structures of the new derivatives of sarsasapogenin, diosgenin and hecogenin thus obtained were established using one and two dimensional (1)H, (13)C experiments (DEPT, COSY, HETCOR, HMBC, ROESY, and NOESY). The X-ray analysis for compound 11b confirmed the 23R configuration for the new stereogenic center.
Collapse
Affiliation(s)
- Yliana López
- Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Ed.B-1, C.U., Morelia, Michoacán 58030, Mexico.
| | | | | | | | | | | |
Collapse
|
15
|
Abstract
Poultry feathers are renewable resources, inexpensive and abundantly available, but have limited applications. Although keratin extracted from feathers has been chemically modified, there are no reports on the chemical modification or development of thermoplastics from poultry feathers. Acetylation is an inexpensive and environmentally friendly approach to make biopolymers thermoplastic. Several biopolymers have been acetylated and used to produce fibers, films, and extrudates. In this research, chicken feathers were acetylated, and the structure and properties of the acetylated feathers were studied. Acetylation conditions such as concentration of chemicals and catalyst and time and temperature of acetylation were optimized. Acetylation of feathers was confirmed using Fourier transform infrared (FTIR) and pyrolysis-gas chromatography-mass spectrometry (P-GC-MS). The acetylated feathers were analyzed using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) to understand their thermal behavior. Acetylated feathers were thermoplastic and could be compression molded to form transparent films despite the relatively low percentage of acetyl content.
Collapse
Affiliation(s)
- Chunyan Hu
- College of Chemistry, Chemical Engineering and Biotechnology, Donghua University , Shanghai 201620, China
| | | | | | | |
Collapse
|
16
|
Abstract
Thymosin beta4 (43 aa) is a highly conserved acidic peptide which regulates actin polymerization in mammalian cells by sequestering globular actin. Thymosin beta4 is undergoing clinical trials as a drug for the treatment of venous stasis ulcers, corneal wounds and injuries, as well as acute myocardial infarction. Currently, thymosin beta4 is produced with solid-phase chemical synthesis. Biotechnological synthesis of this peptide presents difficulties because N-terminal amino acid residue of thymosin beta4 is acetylated. In this study we propose a method for producing the recombinant precursor of thymosin beta4 and its subsequent targeted chemical acetylation. Desacetylthymosin beta4 was synthesized as a part of a hybrid protein with thioredoxin and a specific TEV (tobacco etch virus) protease cleavage site. The following scheme was developed for the purification of desacetylthymosin beta4: (i) the biosynthesis of a soluble hybrid protein (HP) in Escherichia coli; (ii) isolation of the HP by ion exchange chromatography; (iii) cleavage of the HP with TEVprotease; (iv) purification of desacetylthymosin beta4 by ultra-filtration. N-terminal acetylation of desacetylthymosin beta4 was performed with acetic anhydride under acidic conditions (pH 3). The reaction yield was 55%. Thymosin beta4 was then purified by reverse-phase high performance liquid chromatography. The proposed synthetic approach to recombinant thymosin beta4 is suitable for scale-up and can provide for the medical use of highly purified preparation with a yield of 20 mg from 1 L of culture.
Collapse
|
17
|
Yokoyama Y, Nakakoshi M, Okuno H, Sakamoto Y, Sakurai S. Mechanism for the direct synthesis of tryptophan from indole and serine: a useful NMR technique for the detection of a reactive intermediate in the reaction mixture. Magn Reson Chem 2010; 48:811-817. [PMID: 20799376 DOI: 10.1002/mrc.2676] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
The reaction mechanism for the biomimetic synthesis of tryptophan from indole and serine in the presence of Ac(2)O in AcOH was investigated. Although the time-course (1)H-NMR spectra of the reaction of 5-methoxyindole with N-acetylserine were measured in the presence of (CD(3)CO)(2)O in CD(3)CO(2)D, the reactive intermediate could not be detected. This reaction was conducted without 5-methoxyindole in order to elucidate the reactive intermediate, but the intermediate could not be isolated from the reaction mixture. Since the intermediate would be expected to have a very short life time, and therefore be very difficult to detect by conventional analytical methods, the structure of the intermediate was elucidated using a 2D-NMR technique, diffusion-ordered spectroscopy (DOSY). Two intermediates were detected and confirmed to be 2-methyl-4-methyleneoxazol-5(4H)-one and 2-methyl-4-hydroxymethyloxazol-5(4H)-one. The present results demonstrated that DOSY is a powerful tool for the detection of unstable intermediates.
Collapse
Affiliation(s)
- Yuusaku Yokoyama
- Faculty of Pharmaceutical Sciences, Toho University, 2-2-1 Miyama, Funabashi, Chiba 274-8510, Japan.
| | | | | | | | | |
Collapse
|
18
|
Chung WK, Evans ST, Freed AS, Keba JJ, Baer ZC, Rege K, Cramer SM. Utilization of lysozyme charge ladders to examine the effects of protein surface charge distribution on binding affinity in ion exchange systems. Langmuir 2010; 26:759-768. [PMID: 19678624 DOI: 10.1021/la902135t] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
A lysozyme library was employed to study the effects of protein surface modification on protein retention and to elucidate preferred protein binding orientations for cation exchange chromatography. Acetic anhydride was used as an acetylating agent to modify protein surface lysine residues. Partial acetylation of lysozyme resulted in the formation of a homologous set of modified proteins with varying charge densities and distribution. The resulting protein charge ladder was separated on a cation exchange column, and eluent fractions were subsequently analyzed using capillary zone electrophoresis and direct infusion electrospray ionization mass spectrometry. The ion exchange separation showed a significant degree of variation in the retention time of the different variants. Several fractions contained coelution of variants, some with differing net charge. In addition, several cases were observed where variants with more positive surface charge eluted from the column prior to variants with less positive charge. Enzymatic digest followed by mass spectrometry was performed to determine the sites of acetylation on the surface of the variants eluting in various fractions. Electrostatic potential maps of these variants were then generated to provide further insight into the elution order of the variants.
Collapse
Affiliation(s)
- Wai Keen Chung
- Department of Chemical and Biological Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180, USA
| | | | | | | | | | | | | |
Collapse
|
19
|
Richards S, Miller R, Gemperline P. Advantages of soft versus hard constraints in self-modeling curve resolution problems. Penalty alternating least squares (P-ALS) extension to multi-way problems. Appl Spectrosc 2008; 62:197-206. [PMID: 18284796 DOI: 10.1366/000370208783575645] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
An extension to the penalty alternating least squares (P-ALS) method, called multi-way penalty alternating least squares (NWAY P-ALS), is presented. Optionally, hard constraints (no deviation from predefined constraints) or soft constraints (small deviations from predefined constraints) were applied through the application of a row-wise penalty least squares function. NWAY P-ALS was applied to the multi-batch near-infrared (NIR) data acquired from the base catalyzed esterification reaction of acetic anhydride in order to resolve the concentration and spectral profiles of l-butanol with the reaction constituents. Application of the NWAY P-ALS approach resulted in the reduction of the number of active constraints at the solution point, while the batch column-wise augmentation allowed hard constraints in the spectral profiles and resolved rank deficiency problems of the measurement matrix. The results were compared with the multi-way multivariate curve resolution (MCR)-ALS results using hard and soft constraints to determine whether any advantages had been gained through using the weighted least squares function of NWAY P-ALS over the MCR-ALS resolution.
Collapse
Affiliation(s)
- Selena Richards
- Department of Biomolecular Medicine, Division of Surgery, Oncology, Reproductive Biology, and Anaesthetics, Faculty of Medicine, Imperial College London, Sir Alexander Fleming Building, South Kensington, London SW 7 2AZ, United Kingdom
| | | | | |
Collapse
|
20
|
Wang WB, Shen SC, Zhang LY, An H. [Determination of citric acid mono polyethyleneoxide nonyl phenyl ether amber diehylene glycoldinitrate diglycollic amide by IR]. Guang Pu Xue Yu Guang Pu Fen Xi 2007; 27:1121-3. [PMID: 17763772] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
In the present paper, citric acid, acetic anhydride, polyethyleneoxide nonyl phenyl ether and diethanolamine were used as raw materials. The raw materials were purified, and the intermediate products were synthesized. Finally, the citric acid mono polyethyleneoxide nonyl phenyl ether amber diehylene glycol dinitrate diglycollic amide was made. The acidamide of the product synthesized was determined by IR. There is a characteristic peak of C=O in acidamide at 1 642.39 cm(-1). Using potassium rhodanate as a internal standard, and according to Lambert-Beer law, a method to determine the citric acid mono polyethyleneoxide nonyl phenyl ether amber diehylene glycol dinitrate diglycollic amide was developed. The linear regression equation is A = 0.007 6m+0.325 6 with a correlation coefficient (r2) of 0.998 9. The experimental results of the precisions and recoveries are satisfied. The method is very necessary for confirming the reaction extent and controlling quality of citric acid mono polyethyleneoxide nonyl phenyl ether amber diehylene glycol dinitrate diglycollic amide. So, the synthesis process conditions were right according to the IR data.
Collapse
Affiliation(s)
- Wen-Bo Wang
- College of Chemistry and Chemical Engineering, Qiqihar University, Qiqihar 161006, China.
| | | | | | | |
Collapse
|
21
|
Abstract
Under conventional heat (135-145 degrees C) or microwave irradiation and 1 equiv of acetic anhydride, ortho-substituted aryl-oximes undergo a novel sp3 C-H activated cyclization to produce the corresponding isoindoles, and aliphatic oximes afford the corresponding dihydropyrroles. The cyclization occurs with various substrates in good yield (46-82%) leading to unique spiro-fused and cyclic imines. An initial mechanistic investigation suggests the reaction occurs via a nitrenium or vinyl nitrene intermediate. [reaction: see text]
Collapse
Affiliation(s)
- Cécile G Savarin
- Department of Process Research, Merck Research Laboratories, Merck & Co., P.O. Box 2000, Rahway, NJ 07065, USA.
| | | | | | | | | |
Collapse
|
22
|
Abstract
Pleofungins (formerly called F-15078) A, B, C and D, novel depsipeptide antifungal antibiotics, were found in a mycelium extract of the producing fungus, Phoma sp. SANK 13899. The structures of pleofungins A, B, C and D were elucidated mainly by various NMR studies. The absolute configurations of the amino acids and N-methyl amino acids of pleofungin A constituents in the hydrolysate were determined by the application of advanced Marfey's method in combination with gas chromatography/mass spectrometry analysis of their silylation products with N-methyl-N-(tert-butylsilyl)trifluoroacetamide. Two alpha-hydroxy acid constituents, alpha-hydroxyisocaproic acid and alpha-hydroxyisovaleric acid, were isolated from the hydrolysate and their stereochemistries were determined by their specific rotations.
Collapse
Affiliation(s)
- Azusa Aoyagi
- Core Technology Research Laboratories, Sankyo Co., Ltd., Hiromachi, Tokyo, Japan
| | | | | | | |
Collapse
|
23
|
Sanchez A, Ramos Y, Solano Y, González LJ, Betancourt L, Gil J, Padron G, Besada V. Letter: Specific isotope labeling for the identification of free N-terminal peptide of proteins separated by polyacrylamide gel electrophoresis. Eur J Mass Spectrom (Chichester) 2007; 13:307-309. [PMID: 17942980 DOI: 10.1255/ejms.880] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
We report here a method for the identification of free N-terminal peptide of in gel digested isolated proteins. It is based in the difference between the isotopic ion distribution of N-terminal peptide and internal peptides. After guanidination of lysine residues, the primary amino groups of the gel-entrapped protein are blocked with an equimolar mixture of normal and deuterated acetic anhydride. Upon MS analysis internal peptides display a normal isotopic ion distribution while the N-terminal peptide shows a complex isotopic ion distribution.
Collapse
|
24
|
Damianovic MHRZ, Saia FT, Moraes EM, Landgraf D, Rezende MOO, Vazoller RF, Foresti E. Gas chromatographic methods for monitoring of wastewater chlorophenol degradation in anaerobic reactors. J Environ Sci Health B 2007; 42:45-52. [PMID: 17162567 DOI: 10.1080/03601230601020811] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Wastewater samples from an anaerobic reactor were extracted with hexane and derivatized with diazomethane (method 1) and with acetic anidride (method 2). Gas chromatography with electron-capture detection (ECD) was employed for separating the parent compound and intermediates trichlorophenols (TCP) and dichlorophenols (DCP) which originated from the penta chlorophenol (PCP) degradation process. The relations between concentrations of PCP, TCP and DCP areas were linear in the range of concentrations of 0.2 to 8 mg/L and 0.025 mg/L to 5 mg/L for methods 1 and 2, respectively. The repeatability of the extraction methods was satisfactory, with variation coefficients lower than 11%. For method 1, at the fortification level of 0.2 mg/L, recovery of PCP, TCP, and DCP was 112%, 74% and 45%, respectively. For method 2, the corresponding recovery values at the fortification level of 0.1 mg/L were 91%, 93% and 103%, respectively. Storage of the frozen samples did not alter their PCP determination properties. The chromatographic methods adapted for chlorophenol determination in wastewater were suitable with relatively simple manipulation techniques. The obtained results were reproducible and allowed identification of intermediates formed during the PCP degradation process.
Collapse
Affiliation(s)
- Márcia H R Z Damianovic
- Laboratório de Processos Biológicos, Escola de Engenharia de São Carlos, Universidade de São Paulo, São, Carlos-SP, Brazil
| | | | | | | | | | | | | |
Collapse
|
25
|
Romero MD, Calvo L, Alba C, Daneshfar A. A kinetic study of isoamyl acetate synthesis by immobilized lipase-catalyzed acetylation in n-hexane. J Biotechnol 2007; 127:269-77. [PMID: 16959353 DOI: 10.1016/j.jbiotec.2006.07.009] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2005] [Revised: 03/30/2006] [Accepted: 07/04/2006] [Indexed: 11/22/2022]
Abstract
The objective of this work was to propose a reaction mechanism and to develop a rate equation for the synthesis of isoamyl acetate by acylation of the corresponding alcohol with acetic anhydride using the lipase Novozym 435 in n-hexane. The reaction between isoamyl alcohol and acetic anhydride occurred at high rate in first place. Then, if excess alcohol was used, produced acetic acid further reacted with remaining alcohol, leading to yields higher than 100% (based on initial acetic anhydride content). This reaction was much slower and took place only when acetic anhydride had been totally consumed. Optimal pH for Novozym 435 was 7.7. Acetic acid strongly inactivated the enzyme but it was partially caused by the pH drop in the biocatalyst aqueous microenvironment. Acetic anhydride also showed an important inhibition effect. On the contrary, isoamyl alcohol and isoamyl acetate had no negative effect on the lipase. The analysis of the initial rate data showed that reaction followed a Ping-Pong Bi-Bi mechanism with inhibition by acetic anhydride. The kinetic constants were obtained by multiple regression analysis of experimental findings. Equation predictions and experimental reaction rate values matched very well at conditions where acetic acid concentration in the medium was low.
Collapse
Affiliation(s)
- M D Romero
- Departamento de Ingeniería Química, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, Avda. Complutense s/n, 28040 Madrid, Spain
| | | | | | | |
Collapse
|
26
|
Nimesh S, Aggarwal A, Kumar P, Singh Y, Gupta KC, Chandra R. Influence of acyl chain length on transfection mediated by acylated PEI nanoparticles. Int J Pharm 2006; 337:265-74. [PMID: 17254724 DOI: 10.1016/j.ijpharm.2006.12.032] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2006] [Revised: 12/11/2006] [Accepted: 12/15/2006] [Indexed: 09/30/2022]
Abstract
Polyethylenimine (750 kDa) has been derivatized to influence the proton sponge mechanism and hydrophobic-hydrophilic balance. The polymer was acylated using acid anhydrides of varying carbon chain length, followed by cross-linking with PEG-bis-P to form compact nanoparticles. The chemical linkages in the particles were characterized by FTIR and NMR spectroscopy. The hydrodynamic diameter of nanoparticles was found to be in the range of 83.5-124 nm. AFM imaging of native and DNA-loaded nanoparticles revealed highly compact and spherical shape. The positive surface charge on particles decreased with the increase in percentage of acylation and also on complexing with DNA. The buffering capacity of PEI was reduced considerably on preparing acylated nanoparticles. The nanoparticles formed stable complexes with DNA and higher weight ratios were required for formation of electro-neutral complexes. Further, these nanoparticles were investigated for their gene delivery efficacy on COS-1 cells. It was found that acylated PEI nanoparticles were 5-12-fold more efficient transfecting agents as compared to native PEI (750 kDa) and commercially available transfecting agent lipofectin. The MTT colorimetric assay revealed of considerable reduction in toxicity of acylated PEI nanoparticles as compared PEI. Of all the systems prepared, nanoparticles with 30% acylation using propionic anhydride were found to be the most efficient in in vitro transfection.
Collapse
Affiliation(s)
- Surendra Nimesh
- Dr. B.R. Ambedkar Center for Biomedical Research, University of Delhi, Delhi 110007, India
| | | | | | | | | | | |
Collapse
|
27
|
Yamaguchi M, Oka M, Nishida K, Ishida M, Hamazaki A, Kuyama H, Ando E, Okamura TA, Ueyama N, Norioka S, Nishimura O, Tsunasawa S, Nakazawa T. Enhancement of MALDI-MS Spectra of C-Terminal Peptides by the Modification of Proteins via an Active Ester Generated in Situ from an Oxazolone. Anal Chem 2006; 78:7861-9. [PMID: 17105181 DOI: 10.1021/ac0610816] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
For selective C-terminal derivatization of peptides and proteins, we have devised a method for activating the C-terminal carboxyl group by extending the oxazolone chemistry. A mixture of formic acid and acetic anhydride was found to be effective for the formation of an oxazolone, which was converted to an active ester in situ in the presence of a phenol or an N-hydroxide. In particular, the resulting active ester with pentafluorophenol facilitated the subsequent reaction with an amine and the hydrazine derivative to yield the C-terminal amide and hydrazide, respectively. The peptides thus coupled with arginine methyl ester or 2-hydrazino-2-imidazoline containing the guanidino moiety exhibited the positive-ion peaks in matrix-assisted laser desorption/ionization (MALDI) mass spectra with appreciably enhanced intensities. As expected from the reaction mechanism, the carboxyl groups of aspartic and glutamic acid residues were not modified, while the amino groups that could react with the activated peptides were concomitantly protected by formylation. The MALDI peaks corresponding to the C-terminal peptide fragments of proteins were specifically enhanced, discriminating against those from internal peptides that were not tagged with a positive charge. In favorable cases, the C-terminal peptide fragments were clearly discerned by MALDI-MS after chymotryptic digestion and were identified by their MALDI postsource decay analysis. Based on these results, we suggest a method for C-terminal sequencing of a protein.
Collapse
Affiliation(s)
- Minoru Yamaguchi
- Life Science Laboratory, Shimadzu Corporation, Kyoto 604-8511, Japan
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
28
|
Cao Y, Okada Y, Yamada H. Facile and regioselective preparation of partly O-benzylated d-glucopyranose acetates via acid-mediated simultaneous debenzylation–acetolysis. Carbohydr Res 2006; 341:2219-23. [PMID: 16806130 DOI: 10.1016/j.carres.2006.05.018] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2006] [Revised: 05/22/2006] [Accepted: 05/23/2006] [Indexed: 11/24/2022]
Abstract
Fully O-benzylated methyl alpha-D-glucopyranoside shows a steady order in stepwise debenzylation when it is treated with sulfuric acid in acetic anhydride. Based on the order of debenzylation, regioselective preparations of 2,3,4-tri-, 2,3-, 2,4-, 3,4-di-, and 2-O-benzyl-D-glucopyranose acetates were facilitated in greater than 80% yields. The key points of the preparative reactions were the control of the acid strength and choice of suitable substrates.
Collapse
Affiliation(s)
- Yang Cao
- School of Science and Technology, Kwansei Gakuin University, 2-1 Gakuen, Sanda 669-1337, Japan
| | | | | |
Collapse
|
29
|
Abstract
beta-chitin is known to form intercalation complexes with aliphatic alcohols and amines. We found that it also forms complexes with carboxylic anhydrides. When the beta-chitin-acetic anhydride complex was heated to 105 degrees C, the hydroxyl groups of chitin were acetylated by a host-guest reaction, maintaining the host's crystal structure. Structures of complex and acetylated products were analyzed by X-ray diffraction, (13)C CP/MAS NMR, and infrared spectroscopy. The maximum degree of substitution (DS) was close to 1.0, suggesting regioselective esterification at the C6 position of chitin. Partially acetylated beta-chitin with a DS of 0.4 could incorporate various guest species that are difficult to be incorporated by original beta-chitin. In contrast, beta-chitin acetate with a DS of 1 lost the ability to form a complex. Intercalation complexes of beta-chitin with cyclic anhydrides (succinic and maleic) also underwent esterification by heating, and the products with a DS of approximately 1 dissolved in aqueous alkali, apparently as the result of the dissociation of introduced carboxyl groups. These phenomena are potentially useful in controlling the complexation ability of beta-chitin and the preparation of regioselectively esterified chitin derivatives.
Collapse
Affiliation(s)
- A Yoshifuji
- Department of Biomaterials Science, Graduate School of Agricultural & Life Sciences, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113-8657, Japan
| | | | | | | | | |
Collapse
|
30
|
Sánchez A, González LJ, Betancourt L, Gil J, Besada V, Fernández-de-Cossío J, Rodríguez-Ulloa A, Marrero K, Alvarez F, Fando R, Padrón G. Selective isolation of multiple positively charged peptides for 2-DE-free quantitative proteomics. Proteomics 2006; 6:4444-55. [PMID: 16835850 DOI: 10.1002/pmic.200500836] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
A method for quantitative proteomic analysis based on the selective isolation of multiply charged peptides (RH peptides) containing arginine and histidine residues is described. Two pools of proteins are digested in tandem with lysyl-endopeptidase and trypsin and the primary amino groups of proteolytic peptides are separately labeled with d3- and d0-acetic anhydride. This reaction has a dual purpose: (i) to allow the relative protein quantification in two different conditions and (ii) to restrict the positive charges of peptides to the presence of arginine and histidine. The N-acylated peptides are separated by cation-exchange chromatography into two groups, neutral and singly charged peptides (R+H<or=1) that are neither retained nor analyzed, whereas the multiply charged peptides (R+H>1) are retained into the column and can be eluted in batch or further fractionated using a saline gradient before LC-MS/MS analysis. In silico analysis revealed that the selective isolation of RH peptides considerably simplifies the complex mixture of peptides (three RH peptides/protein) and at the same time they represent 84% of the whole proteomes. The selectivity, and recovery of the method were evaluated with model proteins and with a complex mixture of proteins extracted from Vibrio cholerae.
Collapse
Affiliation(s)
- Aniel Sánchez
- Department of Proteomics, Center for Genetic Engineering and Biotechnology, Havana, Cuba
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
31
|
Abstract
Triethylamine and 1-methylimidazole were found to be selective catalysts for the Dakin-West synthesis of diaryl ketones and aryl methyl ketones, respectively. In the 1-methylimidazole-catalyzed reaction, catalysis is due to the simultaneous formation of both an effective acylating agent, 1-acyl-3-methylimidazolium, and a base, carboxylate anion. Hydrocinnamic acid, a compound previously reported to be unreactive under Dakin-West conditions, forms 4-phenyl-2-butanone when the reaction is catalyzed by 1-methylimidazole.
Collapse
Affiliation(s)
- Khanh-Van Tran
- Department of Chemistry, Smith College, Northampton, Massachusetts 01063, USA
| | | |
Collapse
|
32
|
Cao Y, Yamada H. Corrected order in the simultaneous debenzylation–acetolysis of methyl 2,3,4,6-tetra-O-benzyl-α-d-glucopyranoside. Carbohydr Res 2006; 341:909-11. [PMID: 16530739 DOI: 10.1016/j.carres.2006.02.018] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2005] [Revised: 02/01/2006] [Accepted: 02/20/2006] [Indexed: 11/17/2022]
Abstract
The benzyl groups of methyl 2,3,4,6-tetra-O-benzyl-alpha-d-glucopyranoside were cleaved in the order of 6-O-Bn>3-O-Bn>4-O-Bn>2-O-Bn under acid-mediated conditions in acetic anhydride. The order is a correction of that previously reported.
Collapse
Affiliation(s)
- Yang Cao
- School of Science and Technology, Kwansei Gakuin University, 2-1 Gakuen, Sanda 669-1337, Japan
| | | |
Collapse
|
33
|
Stábeli RG, Amui SF, Sant'Ana CD, Pires MG, Nomizo A, Monteiro MC, Romão PRT, Guerra-Sá R, Vieira CA, Giglio JR, Fontes MRM, Soares AM. Bothrops moojeni myotoxin-II, a Lys49-phospholipase A2 homologue: an example of function versatility of snake venom proteins. Comp Biochem Physiol C Toxicol Pharmacol 2006; 142:371-381. [PMID: 16442348 DOI: 10.1016/j.cbpc.2005.11.020] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/22/2005] [Revised: 11/22/2005] [Accepted: 11/23/2005] [Indexed: 10/25/2022]
Abstract
MjTX-II, a myotoxic phospholipase A(2) (PLA(2)) homologue from Bothrops moojeni venom, was functionally and structurally characterized. The MjTX-II characterization included: (i) functional characterization (antitumoral, antimicrobial and antiparasitic effects); (ii) effects of structural modifications by 4-bromophenacyl bromide (BPB), cyanogen bromide (CNBr), acetic anhydride and 2-nitrobenzenesulphonyl fluoride (NBSF); (iii) enzymatic characterization: inhibition by low molecular weight heparin and EDTA; and (iv) molecular characterization: cDNA sequence and molecular structure prediction. The results demonstrated that MjTX-II displayed antimicrobial activity by growth inhibition against Escherichia coli and Candida albicans, antitumoral activity against Erlich ascitic tumor (EAT), human breast adenocarcinoma (SK-BR-3) and human T leukemia cells (JURKAT) and antiparasitic effects against Schistosoma mansoni and Leishmania spp., which makes MjTX-II a promising molecular model for future therapeutic applications, as well as other multifunctional homologous Lys49-PLA(2)s or even derived peptides. This work provides useful insights into the structural determinants of the action of Lys49-PLA(2) homologues and, together with additional strategies, supports the concept of the presence of others "bioactive sites" distinct from the catalytic site in snake venom myotoxic PLA(2)s.
Collapse
Affiliation(s)
- Rodrigo G Stábeli
- Instituto de Pesquisas em Patologias Tropicais, IPEPATRO, Universidade Federal de Rondonia, UNIR-RO, Brazil
| | - Saulo F Amui
- Departamento de Análises Clínicas, Toxicológicas e Bromatológicas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, USP, Ribeirão Preto-SP, Brazil
| | - Carolina D Sant'Ana
- Departamento de Análises Clínicas, Toxicológicas e Bromatológicas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, USP, Ribeirão Preto-SP, Brazil
| | - Matheus G Pires
- Instituto de Pesquisas em Patologias Tropicais, IPEPATRO, Universidade Federal de Rondonia, UNIR-RO, Brazil
| | - Auro Nomizo
- Departamento de Análises Clínicas, Toxicológicas e Bromatológicas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, USP, Ribeirão Preto-SP, Brazil
| | - Marta C Monteiro
- Universidade Estadual do Centro-Oeste/UNICENTRO, Guarapuava-PR, Brazil
| | - Pedro R T Romão
- Laboratório de Imunoparasitologia, UNISUL, Tubarão-SC, Brazil
| | - Renata Guerra-Sá
- Laboratório de Bioquímica e Biologia Molecular-Departamento de Ciências Biológicas, UFOP, Ouro Preto-MG, Brazil
| | - Carlos A Vieira
- Departamento de Bioquímica e Imunologia, FMRP, USP, Ribeirão Preto-SP, Brazil
| | - José R Giglio
- Departamento de Bioquímica e Imunologia, FMRP, USP, Ribeirão Preto-SP, Brazil
| | | | - Andreimar M Soares
- Departamento de Análises Clínicas, Toxicológicas e Bromatológicas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, USP, Ribeirão Preto-SP, Brazil.
| |
Collapse
|
34
|
Abstract
Banana fibers obtained from the sheath of the banana plant (Musa Sapientum) whose major constituent is cellulose were modified using various chemical agents in order to improve their compatibility with the polymer matrix. The change in the surface composition of the raw and chemically modified fiber was investigated using various techniques such as solvatochromism, electrokinetic measurements, and XPS. Surface characterization by XPS showed the presence of numerous elements on the surface of the fiber. Investigation of the surface after alkali treatment on the other hand showed the removal of most of the elements. Silane treatment was found to introduce a considerable amount of silicon on the surface of the fiber. The [O]/[C] ratio was found to decrease in all cases except for the fluorinated and vinyl silane treated fibers. Detailed investigation of the deconvoluted C 1s spectra revealed the change in the percentage atomic concentration of the various elements on the fiber surface. The dissolution of the various surface components by alkali treatment, which was earlier revealed by SEM, was further confirmed by XPS. The XPS results were found to perfectly agree with the solvatochromic and electrokinetic measurements.
Collapse
Affiliation(s)
- L A Pothan
- Post Graduate Department of Chemistry, Bishop Moore College, Mavelikkara, Kerala, India.
| | | | | | | |
Collapse
|
35
|
Abstract
A Zn-salen-modified cavitand templates the catalytic formation of acetylcholine from choline and acetic anhydride.
Collapse
Affiliation(s)
- Felix H Zelder
- Skaggs Institute for Chemical Biology and Department of Chemistry, Scripps Research Institute, MB-26, 10550 North Torrey Pines Road, La Jolla, California 92037, USA
| | | |
Collapse
|
36
|
Tompkins EM, Farmer PB, Lamb JH, Jukes R, Dingley K, Ubick E, Turteltaub KW, Martin EA, Brown K. A novel 14C-postlabeling assay using accelerator mass spectrometry for the detection of O6-methyldeoxy-guanosine adducts. Rapid Commun Mass Spectrom 2006; 20:883-91. [PMID: 16470516 DOI: 10.1002/rcm.2370] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Accelerator mass spectrometry (AMS) is currently one of the most sensitive methods available for the trace detection of DNA adducts and is particularly valuable for measuring adducts in humans or animal models. However, the standard approach requires administration of a radiolabeled compound. As an alternative, we have developed a preliminary 14C-postlabeling assay for detection of the highly mutagenic O6-methyldeoxyguanosine (O6-MedG), by AMS. Procedures were developed for derivatising O6-MedG using unlabeled acetic anhydride. Using conventional liquid chromatography/mass spectrometry (LC/MS) analysis, the limit of detection (LOD) for the major product, triacetylated O6-MedG, was 10 fmol. On reaction of O6-MedG with 14C-acetic anhydride, using a specially designed enclosed system, the predominant product was 14C-di-acetyl O6-MedG. This change in reaction profile was due to a modification of the reaction procedure, introduced as a necessary safety precaution. The LOD for 14C-di-acetyl O6-MedG by AMS was determined as 79 amol, approximately 18,000-fold lower than that achievable by liquid scintillation counting (LSC). Although the assay has so far only been carried out with labeled standards, the degree of sensitivity obtained illustrates the potential of this assay for measuring O6-MedG levels in humans.
Collapse
Affiliation(s)
- Elaine M Tompkins
- Cancer Biomarkers and Prevention Group, Department of Cancer Studies and Molecular Medicine, The Biocentre, University of Leicester, University Road, Leicester LE1 7RH, UK
| | | | | | | | | | | | | | | | | |
Collapse
|
37
|
Abstract
Myosmine is not only one of the minor tobacco alkaloids but is also present in various foods. Therefore, research on myosmine metabolism and activation has been intensified. 3-Pyridylacetic acid, 4-oxo-4-(3-pyridyl)butanoic acid (keto acid), 3-pyridylmethanol, 3'-hydroxymyosmine, and 4-hydroxy-1-(3-pyridyl)-1-butanone (HPB) have been identified as urinary metabolites after oral administration to female Wistar rats. Although N-nitrosation of myosmine, yielding N'-nitrosonornicotine (NNN) and HPB, was considered as a possible in vivo activation route, the formation pathways of most metabolites could not be explained until now. Therefore, under consideration of its high reactivity due to its imine structure, peroxidation of myosmine seemed to be a promising additional activation pathway. In vitro peroxidation using myosmine (8.9 micromol in 200 microL methanol) with a mixture of hydrogen peroxide (57.6 micromol, 5 microL of a 35% solution) and acetic acid anhydride (106 micromol, 10 microL) already showed high yields of reaction products after 30 min ultrasonic treatment. The product pattern was analyzed by HPLC/UV and GC/MS. Besides unchanged myosmine, 3-pyridylacetic acid, keto acid, 3-pyridylmethanol, HPB, and nornicotyrine have been identified as myosmine peroxidation products. Different product patterns were obtained after 24 h and 4 days due to a time-dependent degradation, formation, and conversion of the reaction products. Therefore, peroxidation reaction of myosmine might explain the in vivo formation of 3-pyridylacetic acid, keto acid, 3-pyridylmethanol, and HPB in rats. In addition, because of acetylating conditions using acetic acid anhydride, N-(4-oxo-4-pyridin-3-yl-butyl)acetamide was rapidly formed during the first 30 min of the reaction.
Collapse
Affiliation(s)
- Wolfgang Zwickenpflug
- Walther Straub Institute of Pharmacology and Toxicology, Ludwig-Maximilians University of Munich, Goethestrasse 33, D-80336 Munich, Germany.
| | | |
Collapse
|
38
|
Harjani JR, Nara SJ, Salunkhe MM. Transprotection of silyl ethers of nucleosides in FeCl3 based ionic liquids. Nucleosides Nucleotides Nucleic Acids 2005; 24:819-22. [PMID: 16248043 DOI: 10.1081/ncn-200060305] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Ionic liquid mediated deprotection of tert-butyldimethyl silyl (TBDMS) ethers derived from various primary and secondary alcohols have been studied and the reaction conditions optimized. Deprotection of the silyl ethers in FeCl3 based ionic liquids in presence of acetic anhydride yielded the acetate esters of the corresponding alcohols in good yields. The transprotection methodology was extended to the silyl ethers of nucleosides to yield the corresponding acetylated products.
Collapse
|
39
|
Buvári-Barcza A, Tóth I, Barcza L. Anhydrous formic acid and acetic anhydride as solvent or additive in nonaqueous titrations. Pharmazie 2005; 60:650-5. [PMID: 16222862] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
The use and importance of formic acid and acetic anhydride (Ac2O) is increasing in nonaqueous acid-base titrations, but their interaction with the solutes is poorly understood. This paper attempts to clarify the effect of the solvents; NMR and spectrophotometric investigations were done to reveal the interactions between some bases and the mentioned solvents. Anhydrous formic acid is a typical protogenic solvent but both the relative permittivity and acidity are higher than those of acetic acid (mostly used in assays of bases). These differences originate from the different chemical structures: liquid acetic acid contains basically cyclic dimers while formic acid forms linear associates. Ac2O is obviously not an acidic but an aprotic (very slightly protophilic) solvent, which supposedly dissociates slightly into acetyl (CH3CO+) and acetate (AcO-) ions. In fact, some bases react with Ac2O forming an associate: the Ac+ group is bound to the delta- charged atom of the reactant while AcO- is associated with the delta+ group at appropriate distance.
Collapse
Affiliation(s)
- A Buvári-Barcza
- Department of Inorganic and Analytical Chemistry, Eötvös University, Budapest, Hungary.
| | | | | |
Collapse
|
40
|
Agnihotri G, Tiwari P, Misra AK. One-pot synthesis of per-O-acetylated thioglycosides from unprotected reducing sugars. Carbohydr Res 2005; 340:1393-6. [PMID: 15854611 DOI: 10.1016/j.carres.2005.02.027] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2005] [Revised: 02/25/2005] [Accepted: 02/27/2005] [Indexed: 10/25/2022]
Abstract
A sequential per-O-acetylation and thioglycosidation of unprotected reducing sugars using a stoichiometric quantity of acetic anhydride and alkyl- or arylthiols is reported. These reactions, which are catalyzed by BF3.OEt2, together constitute an efficient one-pot method for the synthesis of acetylated thioglycosides.
Collapse
Affiliation(s)
- Geetanjali Agnihotri
- Medicinal and Process Chemistry Division, Central Drug Research Institute (CDRI), Chattar Manzil Palace, Lucknow 226001, UP, India
| | | | | |
Collapse
|
41
|
Buvári-Barcza A, Barcza L. Problems in the interpretation of nonaqueous titrations. Pharmazie 2005; 60:243-6. [PMID: 15881600] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Most phenomena (like promoting and leveling as well as differentiating effects) of common nonaqueous titrations can be explained by the Brönsted's concept combined with the hydrogen bond theory but some open problems are shown in connection with the use of formic acid and/or acetic anhydride.
Collapse
Affiliation(s)
- A Buvári-Barcza
- Department of Inorganic and Analytical Chemistry, Eötvös University, Budapest, Hungary.
| | | |
Collapse
|
42
|
Fujiwara M, Nishiyama M, Yamamura I, Ohtsuki S, Nomura R. A sol-gel method using acetic anhydride in the presence of cholesterol in organic solution media: preparation of silicas that recognize steroid hormones. Anal Chem 2005; 76:2374-81. [PMID: 15080750 DOI: 10.1021/ac035173w] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Silicas were prepared by a sol-gel method from tetraethoxysilane and acetic anhydride in the presence of cholesterol in organic solution media. Some silicas had higher pore volumes than silicas obtained in the absence of cholesterol. The adsorption abilities by these silicas were compared using various compounds in benzene solution. Although no clear difference among their adsorptions of cholesterol was observed, progesterone and other analogous steroid hormones were well adsorbed by silicas prepared in the presence of cholesterol, especially, prepared with n-heptane as an additional solvent. This silica adsorbed steroid hormones more selectively than other analogous compounds such as bisphenol A and hexestrol. On the other hand, a silica prepared by the usual aqueous sol-gel method with cholesterol had no clear adsorption selectivity to steroid hormones. Furthermore, no selective adsorption of steroid hormones was observed in the case of a common silica gel for column chromatography. This unique property of adsorption observed in silicas prepared using acetic anhydride in the presence of cholesterol is likely to be induced by the imprinting effect of the steroid skeleton part of cholesterol in silica matrix.
Collapse
Affiliation(s)
- Masahiro Fujiwara
- Kansai Center, National Institute of Advanced Industrial Science and Technology (AIST-Kansai), 1 Midorigaoka, Ikeda, Osaka 563-8577, Japan.
| | | | | | | | | |
Collapse
|
43
|
Andreozzi R, Caprio V, Castagnani R, Marotta R, Sanchirico R. (S)-Nitroxycarnitine nitrate production from (S)-carnitine by using acetic anhydride/nitric acid/acetic acid mixtures: safety assessment. J Hazard Mater 2004; 113:1-10. [PMID: 15363509 DOI: 10.1016/j.jhazmat.2004.04.020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2003] [Revised: 04/29/2004] [Accepted: 04/29/2004] [Indexed: 05/24/2023]
Abstract
The present work aims at assessing both thermodynamic and kinetic parameters of the esterification process of the (S)-carnitine, using calorimetric techniques. The use of the system acetic anhydride/nitric acid/acetic acid as esterifying agent and the explosive behaviour of nitric esters lead to safety considerations that have been investigated by hypothesizing some common process deviations. In particular, it has been investigated in adiabatic conditions both the batch addition of acetic anhydride and the effect of an initial temperature higher than those required by the process.
Collapse
Affiliation(s)
- R Andreozzi
- Università di Napoli Federico II, p.le V. Tecchio, 80-80125 Napoli, Italy.
| | | | | | | | | |
Collapse
|
44
|
Martínez-Uruñuela A, González-Sáiz JM, Pizarro C. Optimisation of the derivatisation reaction and subsequent headspace solid-phase microextraction method for the direct determination of chlorophenols in red wine. J Chromatogr A 2004; 1048:141-51. [PMID: 15481251 DOI: 10.1016/j.chroma.2004.07.026] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
An acetylation reaction for the derivatisation of the three chlorophenols involved in cork taint was optimised using a Doehlert design for direct application in wine samples. In this first step, the optimum reaction pH, by adding different amounts of KHCO3, and the required quantity of derivatisation reagent were fixed. Then a series of parameters relevant for the headspace solid-phase microextraction process, such as desorption conditions, salt addition and agitation sample were evaluated. A simultaneous study of the type of fibre and extraction temperature was performed at five levels and based on the results obtained the rest of factors (sample volume and exposition time) that could potentially affect the extraction yields were optimised by a central composite design. According to the validation of the method, we propose here, to our knowledge, the first application of solid-phase microextraction for the direct analysis of chlorophenols in red wine samples.
Collapse
|
45
|
Adebajo MO, Frost RL. Acetylation of raw cotton for oil spill cleanup application: an FTIR and 13C MAS NMR spectroscopic investigation. Spectrochim Acta A Mol Biomol Spectrosc 2004; 60:2315-21. [PMID: 15249021 DOI: 10.1016/j.saa.2003.12.005] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2003] [Accepted: 12/08/2003] [Indexed: 05/13/2023]
Abstract
Fourier transform infrared (FTIR) and 13C MAS NMR spectroscopy have been used to investigate the acetylation of raw cotton samples with acetic anhydride without solvents in the presence of different amounts of 4-dimethylaminopyridine (DMAP) catalyst. This is a continuation of our previous investigation of acetylation of commercial cotton in an effort to develop hydrophobic, biodegradable, cellulosic sorbent materials for cleaning up oil spills. The FTIR data have again provided a clear evidence for successful acetylation. The NMR results further confirm the successful acetylation. The extent of acetylation was quantitatively determined using the weight percent gain (WPG) due to acetylation and by calculating the ratio R between the intensity of the acetyl C=O stretching band at 1740-1745 cm(-1) and the intensity of C-O stretching vibration of the cellulose backbone at about 1020-1040 cm(-1). The FTIR technique was found to be highly sensitive and reliable for the determination of the extent of acetylation. The level of acetylation of the raw cotton samples was found to be much higher than that of cotton fabrics and the previously studied commercial cotton. The variation of the R and WPG with reaction time, amount of DMAP catalyst and different samples of raw cotton is discussed.
Collapse
Affiliation(s)
- Moses O Adebajo
- Inorganic Materials Research Program, School of Physical and Chemical Sciences, Queensland University of Technology, GPO Box 2434, Brisbane Qld 4001, Australia.
| | | |
Collapse
|
46
|
Turner BT, Sabo TM, Wilding D, Maurer MC. Mapping of Factor XIII Solvent Accessibility as a Function of Activation State Using Chemical Modification Methods†. Biochemistry 2004; 43:9755-65. [PMID: 15274630 DOI: 10.1021/bi049260+] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The transglutaminase Factor XIII (FXIII) catalyzes the formation of covalent cross-links between adjacent noncovalently associated fibrin chains in blood coagulation. The resulting covalently cross-linked hard clot is much more mechanically stable and resistant to proteolytic degradation. FXIII is activated by the serine protease thrombin in the presence of calcium ions. Protein modification experiments involving the labeling of cysteine and lysine side chains of the enzyme were performed before and after activation of the enzyme in an effort to gain further insight into structural changes occurring during the activation of FXIII. The experiments revealed differences in the labeling patterns of nonactivated and activated FXIII. These differences result from the exposure or sequestration of specific cysteine or lysine residues when the enzyme is activated, either physiologically with thrombin or nonproteolytically by exposure to calcium. Of note is the acetylation of Lys 73 and Lys 221 upon activation. Both of these residues lie within possible substrate recognition regions of FXIII. The active site Cys 314 is consistently alkylated in the activated enzyme, as is Cys 409, located near the dimer interface. Within the beta-barrel 2 domain of FXIII, Cys 695 becomes alkylated in activated FXIII. Within the same domain, an acetylated Lys (677 or 678), which is observed in the zymogen, cannot be found in the activated enzyme. The results provide a more extensive view of FXIII activation than has been previously available.
Collapse
Affiliation(s)
- Brian T Turner
- Department of Chemistry, University of Louisville, Louisville, Kentucky 40292, USA
| | | | | | | |
Collapse
|
47
|
Abstract
PURPOSE Polyethylenimine (PEI) is a highly effective gene delivery vector, but because it is an off-the shelf material, its properties may not be optimal. To investigate the effects of the protonation properties of the polymer, we generated PEI derivatives by acetylating varying fractions of the primary and secondary amines to form secondary and tertiary amides, respectively. METHODS Reaction of PEI with increasing amounts of acetic anhydride at 60 degrees C for 4.5 h yielded polymers with 15%, 27%, and 43% of the primary amines modified with acetyl groups. Polymer-DNA complexes were characterized by dynamic light scattering and zeta potential measurements. Cytotoxicity of the polymers was assessed by XTT assay for metabolic activity, and gene delivery efficiency was determined as the relative expression of a luciferase gene in MDA-MB-231 and C2C12 cell lines. RESULTS Acetylation of PEI decreased the "physiological buffering capacity," defined as the moles of protons absorbed per mole of nitrogen on titration from pH 7.5 to 4.5, from 0.29 mol H+/mol N to 0.17 mol H+/mot N, 0.12 mol H+/mol N, and 0.090 mol H+/mol N for PEI-Ac15, PEI-Ac27, and PEI-Ac43, respectively. In addition, acetylation decreased the zeta potential of polyplexes from 14 mV to 8-11 mV and increased the polyplex diameter by two- to threefold. Surprisingly, acetylation had a negligible effect on cytotoxicity of the polymers and increased gene delivery effectiveness by up to 21-fold compared to unmodified PEI, both in the presence and absence of serum. CONCLUSIONS Reduction of the buffering capacity of PEI greatly enhanced the gene delivery activity of the polymer. The mechanism is not yet understood, but the enhancement may be caused by more effective polyplex unpackaging, altered endocytic trafficking, and/or increased lipophilicity of acetylated PEI-DNA complexes. Future studies will address these possibilities in more detail.
Collapse
Affiliation(s)
- M Laird Forrest
- Department of Chemical and Biomolecular Engineering, University of Illinois, Urbana, IL 61801, USA
| | | | | | | |
Collapse
|
48
|
Frederiksen H, Frandsen H, Pfau W. Syntheses of DNA adducts of two heterocyclic amines, 2-amino-3-methyl-9H-pyrido[2,3-b]indole (MeAalphaC) and 2-amino-9H-pyrido[2,3-b]indole (AalphaC) and identification of DNA adducts in organs from rats dosed with MeAalphaC. Carcinogenesis 2004; 25:1525-33. [PMID: 15059926 DOI: 10.1093/carcin/bgh156] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
2-Amino-3-methyl-9H-pyrido[2,3-b]indole (MeAalphaC) and 2-amino-3-methyl-9H-pyrido[2,3-b]indole (AalphaC) are mutagenic and carcinogenic heterocyclic amines formed during ordinary cooking. MeAalphaC and AalphaC are activated to mutagenic metabolites by cytochrome P450-mediated N-oxidation to the corresponding N2-OH derivatives. The proximate mutagenic N2-OH derivatives of MeAalphaC and AalphaC did not react with deoxynucleosides or DNA. However, upon acetylation with acetic anhydride both reacted with 2'-deoxyguannosine and 3'-phospho-2'-deoxyguanosine, resulting in one adduct each, but not with other nucleosides or nucleotides. The adducts were identified as N2-(2'-deoxyguanosin-8-yl)-MeAalphaC, N2-(2'-deoxyguanosin-8-yl)-AalphaC, N2-(3'-phospho-2'-deoxyguanosin-8-yl)-MeAalphaC and N2-(3'-phospho-2'-deoxyguanosin-8-yl)-AalphaC by comparison with adducts of known structure obtained by reaction of the parent amines with acetylated guanine N3-oxide. N2-OH-MeAalphaC and N2-OH-AalphaC reacted with calf thymus DNA after addition of acetic anhydride. 32P-postlabelling analysis of modified DNA showed one major adduct co-migrating with N2-(3',5'-diphospho-2'-deoxyguanosin-8-yl)-MeAalphaC and N2-(3',5'-diphospho-2'-deoxyguanosin-8-yl)-AalphaC, respectively. Some minor adducts presumed to be undigested oligomers were also detected. 32P-postlabelling analysis of DNA from several organs of rats dosed orally with MeAalphaC showed that in vivo N2-(2'-deoxyguanosin-8-yl)-MeAalphaC also was the major adduct formed. Relative adduct level in DNA isolated from the liver of the rats was about 50.40 adducts/10(9) nt. The adduct levels were approximately 4-fold lower in the colon and the heart and approximately 12-fold lower in the kidney of the rats.
Collapse
Affiliation(s)
- Hanne Frederiksen
- Institute of Food Safety and Nutrition, Danish Veterinary and Food Administration, Mørkhøj Bygade 19, DK 2860 Søborg, Denmark.
| | | | | |
Collapse
|
49
|
Bernard MP, Cao D, Myers RV, Moyle WR. Tight attachment of chitin-binding-domain-tagged proteins to surfaces coated with acetylated chitosan. Anal Biochem 2004; 327:278-83. [PMID: 15051546 DOI: 10.1016/j.ab.2003.12.029] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2003] [Indexed: 10/26/2022]
Abstract
Several excellent procedures for trapping tagged proteins have been devised, but many of these are expensive, cannot be used outside a limited pH range, fail to work in the presence of chaotropic agents, or are difficult to use. The chitin binding domain (CBD) of Bacillus circulans chitinase, which binds to chitin matrices prepared from inexpensive reagents isolated from crab shells, is an alternative tag that can be used under a variety of pH and denaturing conditions. Kits based on the interaction between the CBD and the chitin beads are available commercially. Here, we show that simultaneous treatment of microtiter plates with chitosan, a deacetylated form of chitin, and acetic anhydride produces a surface-bound film of chitin that also interacts tightly with the CBD. Chitin-coated microtiter well plates captured a CBD-tagged heterodimeric human glycoprotein hormone analog directly from mammalian cell culture media, even when present in trace amounts. Binding to the surface was stable in sodium dodecylsulfate and reversed only partially at low pH or in 8M urea at 37 degrees C. This technique appears well suited to surface attachment and permits biochemical or other analyses of molecules that can be tagged with a CBD.
Collapse
Affiliation(s)
- Michael P Bernard
- Department of Obstetrics and Gynecology, UMDNJ-Robert Wood Johnson (Rutgers) Medical School, Piscataway, NJ 08854, USA
| | | | | | | |
Collapse
|
50
|
Gemperline P, Puxty G, Maeder M, Walker D, Tarczynski F, Bosserman M. Calibration-Free Estimates of Batch Process Yields and Detection of Process Upsets Using in Situ Spectroscopic Measurements and Nonisothermal Kinetic Models: 4-(Dimethylamino)pyridine- Catalyzed Esterification of Butanol. Anal Chem 2004; 76:2575-82. [PMID: 15117200 DOI: 10.1021/ac035356i] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In this paper, we report the use of an NIR fiber-optic spectrometer with a high-speed diode array for calibration-free monitoring and modeling of the reaction of acetic anhydride with butanol using the catalyst 4-(dimethylamino)pyridine in a microscale batch reactor. Acquisition of spectra at 5 ms/scan gave information relevant for modeling these fast batch processes with a single multibatch kinetic model. Nonlinear fitting of a first-principles model directly to the reaction spectra gave calibration-free estimates of time-dependent concentration profiles and pure component spectra. The amount of catalyst was varied between different batches to permit accurate estimation of its effect in the multiway model. A wide range of different models with increasing complexity could be fit to each batch individually with low residuals and apparent low lack of fit. However, only one model properly estimated the concentration profiles when all five batches were fitted simultaneously in a multiway kinetic model. Inclusion of on-line temperature measurements and use of an Arrhenius model for the estimated rate constant gave significantly improved model fits compared to an isothermal kinetic model. Augmentation of prerun batches with data from an additional batch permitted model-based forecasts of reaction trajectories, reaction yield, reaction end points, and process upsets. One batch with added water to simulate a process upset was easily detected by the calibration free process model.
Collapse
Affiliation(s)
- Paul Gemperline
- Department of Chemistry, East Carolina University, Greenville, North Carolina 27858, USA.
| | | | | | | | | | | |
Collapse
|