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Li L, Luo Y, Jia L. Genetically engineered bacterium-modified magnetic particles assisted chiral recognition and colorimetric determination of D/L-tryptophan in millets. Food Chem 2023; 407:135125. [PMID: 36495743 DOI: 10.1016/j.foodchem.2022.135125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Revised: 11/16/2022] [Accepted: 11/28/2022] [Indexed: 12/04/2022]
Abstract
Chiral recognition of enantiomers has always been a thorny issue since they exhibit the same properties under an achiral environment. Herein, polydopamine-functionalized magnetic particles (MP@PDA) were synthesized to immobilize the genetically engineered bacterium Escherichia coli DH5α (MP@PDA-E. coli). L-tryptophan (Trp) instead of D-Trp can be stereo-specifically degraded by tryptophanase in E. coli. The degradation product indole reacts with 4-dimethylaminobenzaldehyde to generate a rose-red adduct. Thus, MP@PDA-E. coli was employed to fabricate a chiral colorimetric method for chiral recognition and determination of L-Trp. The method averts the purification of tryptophanase. More importantly, tryptophanase demonstrates excellent enantioselective ability for L-Trp. The method can not only quantitatively detect L-Trp but also realize the measurement of the enantiomer percentage in the enantiomeric mixture. The feasibility was verified by detecting L-Trp in millet samples from different origins. Furthermore, a portable device was fabricated to make the method more convenient.
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Affiliation(s)
- Ling Li
- Ministry of Education Key Laboratory of Laser Life Science & Guangdong Provincial Key Laboratory of Laser Life Science & Guangzhou Key Laboratory of Spectral Analysis and Functional Probes, College of Biophotonics, South China Normal University, Guangzhou 510631, China
| | - Yimin Luo
- Ministry of Education Key Laboratory of Laser Life Science & Guangdong Provincial Key Laboratory of Laser Life Science & Guangzhou Key Laboratory of Spectral Analysis and Functional Probes, College of Biophotonics, South China Normal University, Guangzhou 510631, China
| | - Li Jia
- Ministry of Education Key Laboratory of Laser Life Science & Guangdong Provincial Key Laboratory of Laser Life Science & Guangzhou Key Laboratory of Spectral Analysis and Functional Probes, College of Biophotonics, South China Normal University, Guangzhou 510631, China.
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2
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Li L, Li C, Jia L. Unlocking the potential of Escherichia coli modified magnetic particles for chiral discrimination of racemic tryptophan. J Chromatogr A 2021; 1659:462638. [PMID: 34731753 DOI: 10.1016/j.chroma.2021.462638] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2021] [Revised: 10/18/2021] [Accepted: 10/20/2021] [Indexed: 11/25/2022]
Abstract
Enzymes possess a highly specific affinity toward their substrates. In this study, an enzyme-based biological method was established for chiral discrimination of D/L-tryptophan (Trp). The polydopamine modified magnetic particles (PDA@Fe3O4) were prepared for immobilization of the genetically engineered bacterium Escherichia coli (E. coli) DH5α. The bacteria-magnetic particles conjugates (bacteria@PDA@Fe3O4) demonstrate excellent chiral discrimination performance toward D/L-Trp at pH 7.0 and 45 °C. The investigation for the principle exhibits that the immobilized E. coli DH5α can produce tryptophanase, and the enzyme can selectively recognize and degrade L-Trp. The Michaelis constant of tryptophanase produced by bacteria@PDA@Fe3O4 was measured to be 25.7 µg mL-1. This method avoids the purification of tryptophanase and unlocks the potential of bacteria modified magnetic particles for chiral discrimination of racemic tryptophan.
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Affiliation(s)
- Ling Li
- Ministry of Education Key Laboratory of Laser Life Science & Guangdong Provincial Key Laboratory of Laser Life Science & Guangzhou Key Laboratory of Spectral Analysis and Functional Probes, College of Biophotonics, South China Normal University, Guangzhou 510631, China
| | - Chuang Li
- Ministry of Education Key Laboratory of Laser Life Science & Guangdong Provincial Key Laboratory of Laser Life Science & Guangzhou Key Laboratory of Spectral Analysis and Functional Probes, College of Biophotonics, South China Normal University, Guangzhou 510631, China
| | - Li Jia
- Ministry of Education Key Laboratory of Laser Life Science & Guangdong Provincial Key Laboratory of Laser Life Science & Guangzhou Key Laboratory of Spectral Analysis and Functional Probes, College of Biophotonics, South China Normal University, Guangzhou 510631, China.
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3
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Dong SL, Xu Y, Chen YZ, Yan XS, Li Z, Xie JW, Jiang YB. Chiral Recognition by Flexible Coordination Polymers of Ag + with a Cysteine-Based Chiral Thiol Ligand That Bears a Binding Site. Inorg Chem 2021; 60:5413-5418. [PMID: 33788549 DOI: 10.1021/acs.inorgchem.1c00104] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
We report a new scheme for chiral recognition using coordination polymers of Ag+ with a chiral thiol ligand that contains a binding group. N-Benzoyl-l-cysteine ethyl ester equipped with a boronic acid group at the para position of the phenyl ring forms coordination polymers with Ag+ in alkaline aqueous solutions that exhibit excellent selectivity toward a d-glucose enantiomer over l-glucose, while the coordination polymers from the d-cysteine-based thiol ligand are specific for l-glucose. It is assumed that a conformation change occurs upon interaction of a saccharide molecule with the polymeric chain receptor, for which the next binding is promoted, leading to the highly effective chiral recognition, despite the flexible nature of the polymeric receptor.
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Affiliation(s)
- Su-Li Dong
- Department of Chemistry, College of Chemistry and Chemical Engineering, Ministry of Education (MOE) Key Laboratory of Spectrochemical Analysis and Instrumentation, and Collaborative Innovation Center of Chemistry for Energy Materials, Xiamen University, Xiamen 361005, China
| | - Yan Xu
- Department of Chemistry, College of Chemistry and Chemical Engineering, Ministry of Education (MOE) Key Laboratory of Spectrochemical Analysis and Instrumentation, and Collaborative Innovation Center of Chemistry for Energy Materials, Xiamen University, Xiamen 361005, China
| | - Yin-Zhu Chen
- Department of Chemistry, College of Chemistry and Chemical Engineering, Ministry of Education (MOE) Key Laboratory of Spectrochemical Analysis and Instrumentation, and Collaborative Innovation Center of Chemistry for Energy Materials, Xiamen University, Xiamen 361005, China
| | - Xiao-Sheng Yan
- Department of Chemistry, College of Chemistry and Chemical Engineering, Ministry of Education (MOE) Key Laboratory of Spectrochemical Analysis and Instrumentation, and Collaborative Innovation Center of Chemistry for Energy Materials, Xiamen University, Xiamen 361005, China
| | - Zhao Li
- Department of Chemistry, College of Chemistry and Chemical Engineering, Ministry of Education (MOE) Key Laboratory of Spectrochemical Analysis and Instrumentation, and Collaborative Innovation Center of Chemistry for Energy Materials, Xiamen University, Xiamen 361005, China
| | - Jian-Wei Xie
- Institute of Pharmacology and Toxicology, Beijing 100027, China
| | - Yun-Bao Jiang
- Department of Chemistry, College of Chemistry and Chemical Engineering, Ministry of Education (MOE) Key Laboratory of Spectrochemical Analysis and Instrumentation, and Collaborative Innovation Center of Chemistry for Energy Materials, Xiamen University, Xiamen 361005, China
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4
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Development and characterization of an electrochemical biosensor for creatinine detection in human urine based on functional molecularly imprinted polymer. J Electroanal Chem (Lausanne) 2017. [DOI: 10.1016/j.jelechem.2017.01.068] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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5
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Ang LF, Por LY, Yam MF. Study on different molecular weights of chitosan as an immobilization matrix for a glucose biosensor. PLoS One 2013; 8:e70597. [PMID: 23940599 PMCID: PMC3734260 DOI: 10.1371/journal.pone.0070597] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2013] [Accepted: 06/21/2013] [Indexed: 11/18/2022] Open
Abstract
Two chitosan samples (medium molecular weight (MMCHI) and low molecular weight (LMCHI)) were investigated as an enzyme immobilization matrix for the fabrication of a glucose biosensor. Chitosan membranes prepared from acetic acid were flexible, transparent, smooth and quick-drying. The FTIR spectra showed the existence of intermolecular interactions between chitosan and glucose oxidase (GOD). Higher catalytic activities were observed on for GOD-MMCHI than GOD-LMCHI and for those crosslinked with glutaraldehyde than using the adsorption technique. Enzyme loading greater than 0.6 mg decreased the activity. Under optimum conditions (pH 6.0, 35°C and applied potential of 0.6 V) response times of 85 s and 65 s were observed for medium molecular weight chitosan glucose biosensor (GOD-MMCHI/PT) and low molecular weight chitosan glucose biosensor (GOD-LMCHI/PT), respectively. The apparent Michaelis-Menten constant ([Formula: see text]) was found to be 12.737 mM for GOD-MMCHI/PT and 17.692 mM for GOD-LMCHI/PT. This indicated that GOD-MMCHI/PT had greater affinity for the enzyme. Moreover, GOD-MMCHI/PT showed higher sensitivity (52.3666 nA/mM glucose) when compared with GOD-LMCHI/PT (9.8579 nA/mM glucose) at S/N>3. Better repeatability and reproducibility were achieved with GOD-MMCHI/PT than GOD-LMCHI/PT regarding glucose measurement. GOD-MMCHI/PT was found to give the highest enzymatic activity among the electrodes under investigation. The extent of interference encountered by GOD-MMCHI/PT and GOD-LMCHI/PT was not significantly different. Although the Nafion coated biosensor significantly reduced the signal due to the interferents under study, it also significantly reduced the response to glucose. The performance of the biosensors in the determination of glucose in rat serum was evaluated. Comparatively better accuracy and recovery results were obtained for GOD-MMCHI/PT. Hence, GOD-MMCHI/PT showed a better performance when compared with GOD-LMCHI/PT. In conclusion, chitosan membranes shave the potential to be a suitable matrix for the development of glucose biosensors.
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Affiliation(s)
- Lee Fung Ang
- School of Pharmaceutical Sciences, Universiti Sains Malaysia, Minden, Penang, Malaysia
| | - Lip Yee Por
- Faculty of Computer Science and Information Technology, University of Malaya, Kuala Lumpur, Malaysia
| | - Mun Fei Yam
- School of Pharmaceutical Sciences, Universiti Sains Malaysia, Minden, Penang, Malaysia
- * E-mail:
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6
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Benavidez TE, Baruzzi AM. Comparative behavior of glucose oxidase and oxalate oxidase immobilized in mucin/chitosan hydrogels for biosensors applications. POLYMER 2012. [DOI: 10.1016/j.polymer.2011.12.014] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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7
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Xu ZX, Gao HJ, Zhang LM, Chen XQ, Qiao XG. The biomimetic immunoassay based on molecularly imprinted polymer: a comprehensive review of recent progress and future prospects. J Food Sci 2011; 76:R69-75. [PMID: 21535786 DOI: 10.1111/j.1750-3841.2010.02020.x] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
UNLABELLED Immunoassay, based on a selective affinity of the biological antibody for its antigen, is one of the most usual analytical methods in food safety and environmental chemistry. However, it presents several drawbacks because of the nature of the antibody. Molecular imprinting technique, due to its high selectivity and stability, ease of preparation and low cost, has shown great potential in producing artificial antibodies in biomimetic immunoassays. This article focuses on the recent states, advantages, current problems and outlooks of molecularly imprinted radio, fluoro, enzyme-linked and chemiluminescent immunoassays, and biomimetic immunosensor, with special emphasis on the challenges in developing biomimetic enzyme-linked immunosorbent assays (BELISAs). The biomimetic immunoassay method will provide an important new analysis platform in food safety, although the sensitivity and specificity is relatively low. PRACTICAL APPLICATION As a new simple analysis method, the biomimetic immunoassay has attractive prospect, although some limitations were existed in real-sample assay. In this critical review, some promising solutions for overcoming its drawbacks were put forward, which may promote the more quick development and extensive application of this method in food safety.
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Affiliation(s)
- Z X Xu
- College of Food Science and Engineering, Shandong Agricultural Univ, Taian 271018, China
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8
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Platonova GA, Tennikova TB. Affinity processes realized on high-flow-through methacrylate-based macroporous monoliths. J Chromatogr A 2005; 1065:19-28. [PMID: 15782946 DOI: 10.1016/j.chroma.2004.12.008] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
The technology for preparation of rigid macroporous polymers suggested in the late 1980s has become a powerful instrument for the development of a novel scientific and practical field. At present, monolithic stationary phases are widely used in the processes of bioseparation (chromatography), bioconversion (enzyme reactors) as well as in other processes based on interphase mass distribution (for example, solid phase peptide and oligonucleotide synthesis). Bioaffinity modes of suggested dynamic methods are very promising for their use in different analytical processes (immunological, ecological, medical and other types of analytical monitoring), preparative isolation of blood proteins such as myoglobin, hemoglobin, immunoglobulins, etc. and also recombinant products directly from cell supernatants or lysates. For the first time, it has been shown that bioaffinity pairing with participation of immobilized on carefully designed rigid supports is very fast and the whole process of affinity separation can be realized within second time scale. The principle of bioaffinity recognition is generaly at the construction of biological reactors (for example, enzyme reactors). Improved kinetics of biocatalized reactions is explained by a minimal influence on the surface of the used sorbent. Very perspective field is the use of discussed monoliths for solid phase chemical synthesis of fragments of biological macromolecules (peptides and oligonucleotides). Several examples of these applications will be presented and discussed.
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Affiliation(s)
- Galina A Platonova
- Institute of Macromolecular Compounds, Russian Academy of Sciences, St Petersburg 199 004, Russia
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9
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Chapter 10 Non-affinity sensing technology: the exploitation of biocatalytic events for environmental analysis. BIOSENSORS AND MODERN BIOSPECIFIC ANALYTICAL TECHNIQUES 2005. [DOI: 10.1016/s0166-526x(05)44010-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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10
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Kandimalla VB, Ju H. Molecular imprinting: a dynamic technique for diverse applications in analytical chemistry. Anal Bioanal Chem 2004; 380:587-605. [PMID: 15480581 DOI: 10.1007/s00216-004-2793-9] [Citation(s) in RCA: 107] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2004] [Revised: 06/22/2004] [Accepted: 07/29/2004] [Indexed: 10/26/2022]
Abstract
Continuous advances in analyzing complex matrices, improving reliability and simplicity, and performing multiple simultaneous assays with extreme sensitivity are increasing. Several techniques have been developed for the quantitative assays of analytes at low concentrations (e.g., high-pressure liquid chromatography, gas chromatography, immunoassay and the polymerase chain reaction technique). To achieve highly specific and sensitive analysis, high affinity, stable, and specific recognition agents are needed. Although biological recognition agents are very specific and sensitive they are labile and/or have a low density of binding sites. During the past decade molecular imprinting has emerged as an attractive and highly accepted tool for the development of artificial recognition agents. Molecular imprinting is achieved by the interaction, either noncovalent or covalent, between complementary groups in a template molecule and functional monomer units through polymerization or polycondensation. These molecularly imprinted polymers have been widely employed for diverse applications (e.g., in chromatographic separation, drug screening, chemosensors, catalysis, immunoassays etc.) owing to their specificity towards the target molecules and high stability against physicochemical perturbations. In this review the advantages, applications, and recent developments in molecular imprinting technology are highlighted.
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Affiliation(s)
- Vivek Babu Kandimalla
- Department of Chemistry, Key Laboratory of Analytical Chemistry for Life Science (Chinese Ministry of Education), Nanjing University, Nanjing 210093, China
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11
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Tozzi C, Anfossi L, Giraudi G. Affinity chromatography techniques based on the immobilisation of peptides exhibiting specific binding activity. J Chromatogr B Analyt Technol Biomed Life Sci 2004; 797:289-304. [PMID: 14630156 DOI: 10.1016/s1570-0232(03)00481-1] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Affinity chromatography is one of the powerful techniques in selective purification and isolation of a great number of compounds. New challenges in scientific research, such as high-throughput systems, isolation procedures that allow to obtain a single substance from a complex matrix in high degree of purity, low costs and wide availability, have led to the discovery of new tailor-made synthetic recognition systems. In this review the design, synthesis, purification and characterisation of peptides with recognition properties are discussed. Applications of peptide ligands are described and analytical tools mentioned.
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Affiliation(s)
- Cinzia Tozzi
- Department of Analytical Chemistry, University of Turin, Via P. Giuria 5, 10125 Turin, Italy.
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12
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Burns KL, May SW. Separation methods applicable to the evaluation of enzyme-inhibitor and enzyme-substrate interactions. J Chromatogr B Analyt Technol Biomed Life Sci 2004; 797:175-90. [PMID: 14630149 DOI: 10.1016/j.jchromb.2003.08.038] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Enzymes catalyze a rich variety of metabolic transformations, and do so with very high catalytic rates under mild conditions, and with high reaction regioselectivity and stereospecificity. These characteristics make biocatalysis highly attractive from the perspectives of biotechnology, analytical chemistry, and organic synthesis. This review, containing 128 references, focuses on the use of separation techniques in the elucidation of enzyme-inhibitor and enzyme-substrate interactions. While coverage of the literature is selective, a broad perspective is maintained. Topics considered include chromatographic methods with soluble or immobilized enzymes, capillary electrophoresis, biomolecular interaction analysis tandem mass spectrometry (BIA-MS), phage and ribosomal display, and immobilized enzyme reactors (IMERs). Examples were selected to demonstrate the relevance and application of these methods for determining enzyme kinetic parameters, ranking of enzyme inhibitors, and stereoselective synthesis and separation of chiral entities.
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Affiliation(s)
- Kristi L Burns
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta 30332, GA, USA
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Bertucci C, Bartolini M, Gotti R, Andrisano V. Drug affinity to immobilized target bio-polymers by high-performance liquid chromatography and capillary electrophoresis. J Chromatogr B Analyt Technol Biomed Life Sci 2003; 797:111-29. [PMID: 14630146 DOI: 10.1016/j.jchromb.2003.08.033] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This review addresses the use of high-performance liquid chromatography (HPLC) and capillary electrophoresis (CE) as affinity separation methods to characterise drugs or potential drugs-bio-polymer interactions. Targets for the development of new drugs such as enzymes (IMERs), receptors, and membrane proteins were immobilized on solid supports. After the insertion in the HPLC system, these immobilized bio-polymers were used for the determination of binding constants of specific ligands, substrates and inhibitors of pharmaceutical interest, by frontal analyses and zonal elution methods. The most used bio-polymer immobilization techniques and methods for assessing the amount of active immobilized protein are reported. Examples of increased stability of immobilized enzymes with reduced amount of used protein were shown and the advantages in terms of recovery for reuse, reproducibility and on-line high-throughput screening for potential ligands are evidenced. Dealing with the acquisition of relevant pharmacokinetic data, examples concerning human serum albumin binding studies are reviewed. In particular, papers are reported in which the serum carrier has been studied to monitor the enantioselective binding of chiral drugs and the mutual interaction between co-administered drugs by CE and HPLC. Finally CE, as merging techniques with very promising and interesting application of microscale analysis of drugs' binding parameters to immobilized bio-polymers is examined.
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Affiliation(s)
- C Bertucci
- Dipartimento di Scienze Farmaceutiche, Università di Bologna, Via Belmeloro 6, 40126 Bologna, Italy
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14
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Kanie Y, Kanie O. Electrophoretically mediated microscale reaction of glycosidases: kinetic analysis of some glycosidases at the nanoliter scale. Carbohydr Res 2002; 337:1757-62. [PMID: 12423954 DOI: 10.1016/s0008-6215(02)00135-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Capillary electrophoresis (CE) is one of the extremely important analytical techniques known for its high sensitivity and resolution. We have investigated electrophoretically mediated microanalysis (EMMA) for the assay of some native glycosidases. Under optimized conditions, the enzymatic reactions of alpha-glucosidase, beta-galactosidase and beta-N-acetylglucosaminidase were carried out, and the Michaelis constants were obtained. The current method may have advantages over traditional assay methods, especially in terms of the amount of enzyme and substrate required for a reaction.
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Affiliation(s)
- Yoshimi Kanie
- Mitsubishi Kagaku Institute of Life Sciences (MLTILS), Machida-shi, 194-8511, Tokyo, Japan
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Podgornik A, Tennikova TB. Chromatographic reactors based on biological activity. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2002; 76:165-210. [PMID: 12126268 DOI: 10.1007/3-540-45345-8_5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Abstract
In the last decade there were many papers published on the study of enzyme catalyzed reactions performed in so-called chromatographic reactors. The attractive feature of such systems is that during the course of the reaction the compounds are already separated, which can drive the reaction beyond the thermodynamic equilibrium as well as remove putative inhibitors. In this chapter, an overview of such chromatographic bioreactor systems is given. Besides, some immobilization techniques to improve enzyme activity are discussed together with modern chromatographic supports with improved hydrodynamic characteristics to be used in this context.
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Abstract
Catalytic chromatography exploits both specific biological affinity and catalytic specificity to selectively purify enzymes. Two different applications are presented. Purification of EcoRI restriction endonuclease to apparent homogeneity was accomplished in a single step with significantly greater yield and purification than was obtained with affinity chromatography. An attempt to purify the multiple DNA polymerase activities of Escherichia coli was also developed. Five well-resolved peaks of DNA polymerase activity were fractionated. In this new chromatographic mode, the enzyme binds immobilized substrate coupled to a column in the absence of some required cofactor. When the missing cofactor is added, the enzyme converts substrate to product and selectively elutes from the column.
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Affiliation(s)
- L A Jurado
- Department of Biochemistry, University of Tennessee, 858 Madison Avenue, Memphis, Tennessee 38163, USA
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Abstract
An analytical method for studying enzyme inhibition has been developed using capillary electrophoresis with laser-induced fluorescence detection. This technique is based on electrophoretic mixing of zones of enzyme and inhibitor in substrate-filled capillaries. Enzyme catalytic activity is measured by detecting the fluorescent reaction product as it migrates past the detector. Reversible enzyme inhibition is indicated by a transient decrease in product formation. The enzyme, alkaline phosphatase, has been studied using the fluorogenic substrate AttoPhos ([2,2'-bibenzothiazol]-6-hydroxy-benzthiazole phosphate). This assay has been used to quantify theophylline, a noncompetitive, reversible inhibitor of alkaline phosphatase. The detection limit for theophylline is estimated at 3 microM, and 8.6 amole of alkaline phosphatase are required for each assay. The calculated K(i) for theophylline is 90 microM for the capillary electrophoretic enzyme-inhibitor assays.
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Affiliation(s)
- A R Whisnant
- Department of Chemistry, The University of Tennessee, Knoxville 37996-1600, USA
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