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Rodrigues MO, Eberlin MN, Neto BAD. How and Why to Investigate Multicomponent Reactions Mechanisms? A Critical Review. CHEM REC 2021; 21:2762-2781. [PMID: 33538117 DOI: 10.1002/tcr.202000165] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Revised: 01/04/2021] [Indexed: 01/03/2023]
Abstract
We review the most innovative efforts and greatest challenges faced when elucidating multicomponent reactions (MCRs) mechanisms. When compared to traditional reactions, the often two or more concurrent reactions pathways and the greater number of possible intermediates in MCRs turn their mechanistic investigation both a harder and trickier task. The common approaches used to investigate reaction mechanisms are often unable to clarify MCRs mechanisms; hence few but clever approaches are currently used to determine these mechanisms and to depict their key transformations. Their complexity has required most innovative approaches and the use of a number of unique techniques that have shed light over the favored pathway selected from the myriad of alternatives theoretically available for MCRs. This review focuses on the most successful efforts applied by a few leading groups to perform these puzzlingly investigations.
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Affiliation(s)
- Marcelo O Rodrigues
- Laboratory of Medicinal and Technological Chemistry, University of Brasília, Chemistry Institute (IQ-UnB), Campus Universitário Darcy Ribeiro, Brasília, Distrito Federal, 70904-970, Brazil.,School of Physics and Astronomy, Nottingham University, NG72RD, Nottingham, U.K
| | - Marcos N Eberlin
- MackMass Laboratory, PPGENM, School of Engineering, Mackenzie Presbyterian University, São Paulo, SP, 01302-907, Brazil
| | - Brenno A D Neto
- Laboratory of Medicinal and Technological Chemistry, University of Brasília, Chemistry Institute (IQ-UnB), Campus Universitário Darcy Ribeiro, Brasília, Distrito Federal, 70904-970, Brazil
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2
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Adamu A, Wahab RA, Aliyu F, Aminu AH, Hamza MM, Huyop F. Haloacid dehalogenases of Rhizobium sp. and related enzymes: Catalytic properties and mechanistic analysis. Process Biochem 2020. [DOI: 10.1016/j.procbio.2020.02.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Adamu A, Wahab RA, Huyop F. l-2-Haloacid dehalogenase (DehL) from Rhizobium sp. RC1. SPRINGERPLUS 2016; 5:695. [PMID: 27347470 PMCID: PMC4899344 DOI: 10.1186/s40064-016-2328-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Accepted: 05/11/2016] [Indexed: 11/10/2022]
Abstract
l-2-Haloacid dehalogenase (DehL) from Rhizobium sp. RC1 is a stereospecific enzyme that acts exclusively on l-isomers of 2-chloropropionate and dichloroacetate. The amino acid sequence of this enzyme is substantially different from those of other l-specific dehalogenases produced by other organisms. DehL has not been crystallised, and hence its three-dimensional structure is unavailable. Herein, we review what is known concerning DehL and tentatively identify the amino acid residues important for catalysis based on a comparative structural and sequence analysis with well-characterised l-specific dehalogenases.
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Affiliation(s)
- Aliyu Adamu
- Department of Biotechnology and Medical Engineering, Faculty of Biosciences and Medical Engineering, Universiti Teknologi Malaysia, 81310 Johor Baharu, Johor Malaysia
| | - Roswanira Abdul Wahab
- Department of Chemistry, Faculty of Science, Universiti Teknologi Malaysia, 81310 Johor Baharu, Johor Malaysia
| | - Fahrul Huyop
- Department of Biotechnology and Medical Engineering, Faculty of Biosciences and Medical Engineering, Universiti Teknologi Malaysia, 81310 Johor Baharu, Johor Malaysia
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Kondo H, Fujimoto KJ, Tanaka S, Deki H, Nakamura T. Theoretical prediction and experimental verification on enantioselectivity of haloacid dehalogenase l-DEX YL with chloropropionate. Chem Phys Lett 2015. [DOI: 10.1016/j.cplett.2015.01.053] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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5
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A Mechanistic Analysis of Enzymatic Degradation of Organohalogen Compounds. Biosci Biotechnol Biochem 2014; 75:189-98. [DOI: 10.1271/bbb.100746] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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6
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Siwek A, Omi R, Hirotsu K, Jitsumori K, Esaki N, Kurihara T, Paneth P. Binding modes of DL-2-haloacid dehalogenase revealed by crystallography, modeling and isotope effects studies. Arch Biochem Biophys 2013; 540:26-32. [DOI: 10.1016/j.abb.2013.09.012] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2013] [Revised: 09/14/2013] [Accepted: 09/17/2013] [Indexed: 11/30/2022]
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Liu J, Zheng M, Zhang C, Xu D. “Amide Resonance” in the Catalysis of 1,2-α-l-Fucosidase from Bifidobacterium bifidum. J Phys Chem B 2013; 117:10080-92. [DOI: 10.1021/jp402110j] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Jingli Liu
- Key
Laboratory of Green Chemistry and Technology, College
of Chemistry, Ministry of Education, Chengdu, Sichuan 610064, P. R. China
| | - Min Zheng
- Key
Laboratory of Green Chemistry and Technology, College
of Chemistry, Ministry of Education, Chengdu, Sichuan 610064, P. R. China
| | - Chunchun Zhang
- Testing & Analytical Center, Sichuan University, Chengdu, Sichuan 610064, P. R. China
| | - Dingguo Xu
- Key
Laboratory of Green Chemistry and Technology, College
of Chemistry, Ministry of Education, Chengdu, Sichuan 610064, P. R. China
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Mersfelder EL, Parthun MR. Involvement of Hat1p (Kat1p) catalytic activity and subcellular localization in telomeric silencing. J Biol Chem 2008; 283:29060-8. [PMID: 18753131 DOI: 10.1074/jbc.m802564200] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Previous studies have shown that loss of the type B histone acetyltransferase Hat1p leads to defects in telomeric silencing in Saccharomyces cerevisiae. We used this phenotype to explore a number of functional characteristics of this enzyme. To determine whether the enzymatic activity of Hat1p is necessary for its role in telomeric silencing, a structurally conserved glutamic acid residue (Glu-255) that has been proposed to be the enzymes catalytic base was mutated. Surprisingly neither this residue nor any other acidic residues near the enzymes active site were essential for enzymatic activity. This suggests that Hat1p differs from most histone acetyltransferases in that it does not use an acidic amino acid as a catalytic base. The effects of these Hat1p mutants on enzymatic activity correlated with their effects on telomeric silencing indicating that the ability of Hat1p to acetylate substrates is important for its in vivo function. Despite its presumed role in the acetylation of newly synthesized histones in the cytoplasm, Hat1p was found to be a predominantly nuclear protein. This subcellular localization of Hat1p is important for its in vivo function because a construct that prevents its accumulation in the nucleus caused defects in telomeric silencing similar to those seen with a deletion mutant. Therefore, the presence of catalytically active Hat1p in the cytoplasm is not sufficient to support normal telomeric silencing. Hence both enzymatic activity and nuclear localization are necessary characteristics of Hat1p function in telomeric silencing.
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Affiliation(s)
- Erica L Mersfelder
- Department of Molecular and Cellular Biochemistry, The Ohio State University, Columbus, Ohio 43210, USA
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Kurihara T, Esaki N. Bacterial hydrolytic dehalogenases and related enzymes: Occurrences, reaction mechanisms, and applications. CHEM REC 2008; 8:67-74. [DOI: 10.1002/tcr.20141] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Schmidberger JW, Wilce JA, Tsang JSH, Wilce MCJ. Crystal structures of the substrate free-enzyme, and reaction intermediate of the HAD superfamily member, haloacid dehalogenase DehIVa from Burkholderia cepacia MBA4. J Mol Biol 2007; 368:706-17. [PMID: 17368477 DOI: 10.1016/j.jmb.2007.02.015] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2006] [Revised: 02/02/2007] [Accepted: 02/07/2007] [Indexed: 11/17/2022]
Abstract
DehIVa is a haloacid dehalogenase (EC 3.8.1.2) from the soil and water borne bacterium Burkholderia cepacia MBA4, which belongs to the functionally variable haloacid dehalogenase (HAD) superfamily of enzymes. The haloacid dehalogenases catalyse the removal of halides from haloacids resulting in a hydroxlated product. These enzymes are of interest for their potential to degrade recalcitrant halogenated environmental pollutants and their use in the synthesis of industrial chemicals. The haloacid dehalogenases utilise a nucleophilic attack on the substrate by an aspartic acid residue to form an enzyme-substrate ester bond and concomitantly cleaving of the carbon-halide bond and release of a hydroxylated product following ester hydrolysis. We present the crystal structures of both the substrate-free DehIVa refined to 1.93 A resolution and DehIVa covalently bound to l-2-monochloropropanoate trapped as a reaction intermediate, refined to 2.7 A resolution. Electron density consistent with a previously unidentified yet anticipated water molecule in the active site poised to donate its hydroxyl group to the product and its proton to the catalytic Asp11 is evident. It has been unclear how substrate enters the active site of this and related enzymes. The results of normal mode analysis (NMA) are presented and suggest a means whereby the predicted global dynamics of the enzyme allow for entry of the substrate into the active site. In the context of these results, the possible role of Arg42 and Asn178 in a "lock down" mechanism affecting active site access is discussed. In silico substrate docking of enantiomeric substrates has been examined in order to evaluate the enzymes enantioselectivity.
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Affiliation(s)
- Jason W Schmidberger
- School of Medicine and Pharmacology, The University of Western Australia, Perth, Australia
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11
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Liesener A, Karst U. Turbulent flow chromatography for the reduction of matrix effects in electrospray ionization mass spectrometry-based enzyme assays. J Sep Sci 2005; 28:1658-65. [PMID: 16224959 DOI: 10.1002/jssc.200500090] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Turbulent flow chromatography (TFC) is presented as a means to reduce ion suppression in simultaneous multianalyte mass spectrometric bioassays. In this study, the effects of enzymes present in the sample on the signal response of five analytes were simultaneously investigated over a protein content range from 0 to 38 microg/mL by means of direct flow injection MS. As model enzymes, trypsin, thrombin, and chymotrypsin were selected. Without employment of TFC, both signal suppression and signal enhancement, depending on the nature of the analyte and the amount of matrix in the sample, were observed. Generally, these matrix effects were found to be intolerably large. The deviation from the mean signal response as a measure of deterioration was found to be between 14 and 112%. The addition of an excess of methanol as means of sample clean-up was investigated and found not to be sufficient. By employing TFC for online sample preparation, it was possible to reduce the matrix effecTs to a minimum for all model systems investigated. In case of trypsin the distortion could be lowered from 41.9 to 2.6%. Thus, TFC is considered to be a highly valuable tool for improving the sensitivity and reliability in the monitoring of enzymatic conversions by means of MS.
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Affiliation(s)
- André Liesener
- Chemical Analysis Group and MESA Research Institute, University of Twente, Enschede, The Netherlands
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Fabris D. Mass spectrometric approaches for the investigation of dynamic processes in condensed phase. MASS SPECTROMETRY REVIEWS 2005; 24:30-54. [PMID: 15389863 DOI: 10.1002/mas.20007] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Mass spectrometry (MS) offers many advantages over other established spectroscopic techniques employed for the investigation of processes in condensed phase. The sensitivity, specificity, and speed afforded by MS-based methods enable to obtain very valuable insights into the mechanism of complex dynamic processes. Off-line methods rely on quenching to halt the progress of the reaction of interest and allow for the implementation of a broad range of analytical procedures for sample fractionation, isolation, or desalting. On the contrary, on-line methods are designed to carry out the real-time monitoring of dynamic processes through a continuous uninterrupted analysis of reaction mixtures, with the only caveat that the sample solutions be directly amenable to the available ionization technique. The utilization of rapid mixing devices in direct connection with a mass spectrometer or included in off-line schemes provides access to the initial moments of a reaction, which can offer very important information about the reaction mechanism. This report summarizes the different off- and on-line strategies developed to study chemical and biochemical reactions in solution and obtain kinetic/mechanistic information. The merits of the various experimental designs, the characteristics of the different instrumental setups, and the factors affecting time resolution are discussed with the aid of specific examples, which highlight the contributions of MS to the different facets of the investigation of dynamic processes in condensed phase.
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Affiliation(s)
- Daniele Fabris
- Department of Chemistry and Biochemistry, University of Maryland, Baltimore County, Baltimore, Maryland 21250, USA.
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Liesener A, Perchuc AM, Schöni R, Wilmer M, Karst U. Screening for proteolytic activities in snake venom by means of a multiplexing electrospray ionization mass spectrometry assay scheme. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2005; 19:2923-8. [PMID: 16175652 DOI: 10.1002/rcm.2136] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
A multiplexed mass spectrometry based assay scheme for the simultaneous determination of five different substrate/product pairs was developed as a tool for screening of proteolytic activities in snake venom fractions from Bothrops moojeni. The assay scheme was employed in the functional characterization of eight model proteases. Time-resolved reaction profiles were generated and the relative reaction progress at each time point was determined. These were used to semi-quantitatively sort the catalytic activities of each enzyme towards the respective substrates into six classes. The resulting activity pattern served as an activity fingerprint for each enzyme. The multiplex assay scheme was then applied to a screening for proteolytic activities in fractions of the pre-separated venom from B. moojeni. Activity patterns of each fraction were generated and used to sort the fractions into three different categories of activity. By comparison of the fingerprint activity patterns of the venom fractions and the model enzymes, a compound with proteolytic properties similar to activated protein C was detected.
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Affiliation(s)
- André Liesener
- University of Twente, Chemical Analysis Group and MESA+ Institute for Nanotechnology, P.O. Box 217, 7500 AE Enschede, The Netherlands
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Liesener A, Karst U. Assessing protease activity pattern by means of multiple substrate ESI-MS assays. Analyst 2005; 130:850-4. [PMID: 15912232 DOI: 10.1039/b502008e] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The development of a simultaneous multiple substrate enzymatic assay based on electrospray ionization mass spectrometry (ESI-MS) detection is described. This multiplexing assay scheme was employed in a parallel proteolytic enzyme activity screening. As model systems, the respective activities of trypsin, thrombin, chymotrypsin, bromelain, ficin and elastase towards seven different substrates were assessed. The resulting activity patterns were evaluated semi-quantitatively ranking the enzymatic activities in five classes of activity (very high, high, medium, low and no activity) with respect to the individual substrates. The validity of the MS-based multiplexing assay scheme was proved by comparison with the results obtained from single substrate assays detected by means of UV/vis absorption at 405 nm, showing good agreement of the resulting activity patterns and classifications.
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Affiliation(s)
- André Liesener
- University of Twente, Department of Chemical Analysis, P. O. Box 217, 7500 AE Enschede, The Netherlands
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Ichiyama S, Kurihara T, Kogure Y, Tsunasawa S, Kawasaki H, Esaki N. Reactivity of asparagine residue at the active site of the D105N mutant of fluoroacetate dehalogenase from Moraxella sp. B. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2004; 1698:27-36. [PMID: 15063312 DOI: 10.1016/j.bbapap.2003.10.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2003] [Revised: 10/02/2003] [Accepted: 10/03/2003] [Indexed: 11/30/2022]
Abstract
Fluoroacetate dehalogenase from Moraxella sp. B (FAc-DEX) catalyzes cleavage of the carbon-fluorine bond of fluoroacetate, whose dissociation energy is among the highest found in natural products. Asp105 functions as the catalytic nucleophile that attacks the alpha-carbon atom of the substrate to displace the fluorine atom. In spite of the essential role of Asp105, we found that site-directed mutagenesis to replace Asp105 by Asn does not result in total inactivation of the enzyme. The activity of the mutant enzyme increased in a time- and temperature-dependent manner. We analyzed the enzyme by ion-spray mass spectrometry and found that the reactivation was caused by the hydrolytic deamidation of Asn105 to generate the wild-type enzyme. Unlike Asn10 of the l-2-haloacid dehalogenase (L-DEX YL) D10N mutant, Asn105 of the fluoroacetate dehalogenase D105N mutant did not function as a nucleophile to catalyze the dehalogenation.
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Affiliation(s)
- Susumu Ichiyama
- Laboratory of Microbial Biochemistry, Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
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Su P, Scheiner-Bobis G. Lys691 and Asp714 of the Na+/K+-ATPase α Subunit Are Essential for Phosphorylation, Dephosphorylation, and Enzyme Turnover. Biochemistry 2004; 43:4731-40. [PMID: 15096042 DOI: 10.1021/bi049884f] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
P-type ATPases such as the sodium pump appear to be members of a superfamily of hydrolases structurally typified by the L-2-haloacid dehalogenases. In the dehalogenase L-DEX-ps, Lys151 serves to stabilize the excess negative charge in the substrate/reaction intermediates and Asp180 coordinates a water molecule that is directly involved in ester intermediate hydrolysis. To investigate the importance of the corresponding Lys691 and Asp714 of the sodium pump alpha subunit, sodium pump mutants were expressed in yeast and analyzed for their properties. Lys691Ala, Lys691Asp, Asp714Ala, and Asp714Arg mutants were inactive, not only with respect to ATPase activity but also to interaction with the highly sodium pump-specific inhibitors ouabain or palytoxin (PTX). In contrast, conservative mutants Lys691Arg and Asp714Glu retained some of the partial activities of the wild-type enzyme, although they completely failed to display any ATPase activity. Yeast cells expressing Lys691Arg and Asp714Glu mutants are sensitive to the sodium pump-specific inhibitor PTX and lose intracellular K+. Their sensitivity to PTX, with EC50 values of 118 +/- 24 and 76.5 +/- 3.6 nM, respectively, was clearly reduced by almost 7- or 4-fold below that of the native sodium pump (17.8 +/- 2.7 nM). Ouabain was recognized under these conditions with low affinity by the mutants and inhibited the PTX-induced K+ efflux from the yeast cells. The EC50 for the ouabain effect was 183 +/- 20 microM for Lys691Arg and 2.3 +/- 0.08 mM for the Asp714Glu mutant. The corresponding value obtained with cells expressing the native sodium pump was 69 +/- 18 microM. In the presence of Pi and Mg2+, none of the mutant sodium pumps were able to bind ouabain. When Mg2+ was omitted, however, both Lys691Asp and Asp714Glu mutants displayed ouabain binding that was reduced by Mg2+ with an EC50 of 0.76 +/- 0.11 and 2.3 +/- 0.2 mM, respectively. In the absence of Mg2+, ouabain binding was also reduced by K+. The EC50 values were 1.33 +/- 0.23 mM for the wild-type enzyme, 0.93 +/- 0.2 mM for the Lys691Arg mutant, and 1.02 +/- 0.24 mM for the Asp714Glu enzyme. None of the neutral or nonconservative mutants displayed any ouabain-sensitive ATPase activity. Ouabain-sensitive phosphatase activity, however, was present in membranes containing either the wild-type (1105 +/- 100 micromol of p-nitrophenol phosphate hydrolyzed min(-1) mg of protein(-1)) or the Asp714Glu mutant (575 +/- 75 micromol min(-1) mg(-1)) sodium pump. Some phosphatase activity was also associated with the Lys691Arg mutant (195 +/- 63 micromol min(-1) mg(-1)). The results are consistent with Lys691 and Asp714 being essential for the phosphorylation/dephosphorylation process that allows the sodium pump to accomplish the catalytic cycle.
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Affiliation(s)
- Ping Su
- Institut für Biochemie und Endokrinologie, Fachbereich Veterinärmedizin, Justus-Liebig-Universität Giessen, Frankfurter Strasse 100, D-35392 Giessen, Germany
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Pi N, Leary JA. Determination of enzyme/substrate specificity constants using a multiple substrate ESI-MS assay. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2004; 15:233-243. [PMID: 14766290 DOI: 10.1016/j.jasms.2003.10.009] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2003] [Revised: 10/09/2003] [Accepted: 10/10/2003] [Indexed: 05/24/2023]
Abstract
The traditional method used to investigate the reaction specificity of an enzyme with different substrates is to perform individual kinetic measurements. In this case, a series of varied concentrations are required to study each substrate and a non-regression analysis program is used several times to obtain all the specificity constants for comparison. To avoid the large amount of experimental materials, long analysis time, and redundant data processing procedures involved in the traditional method, we have developed a novel strategy for rapid determination of enzyme substrate specificity using one reaction system containing multiple competing substrates. In this multiplex assay method, the electrospray ionization mass spectrometry (ESI-MS) technique was used for simultaneous quantification of multiple products and a steady-state kinetics model was established for efficient specificity constant calculation. The system investigated was the bacterial sulfotransferase NodH (NodST), which is a host specific nod gene product that catalyzes the sulfate group transfer from 3'-phosphoadenosine 5'-phosphosulfate (PAPS) to natural Nod factors or synthetic chitooligosaccharides. Herein, the reaction specificity of NodST for four chitooligosaccharide acceptor substrates of different chain length (chitobiose, chitotriose, chitotetraose, and chitopentaose) was determined by both individual kinetic measurements and the new multiplex ESI-MS assay. The results obtained from the two methods were compared and found to be consistent. The multiplex ESI-MS assay is an accurate and valid method for substrate specificity evaluation, in which multiple substrates can be evaluated in one assay.
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Affiliation(s)
- Na Pi
- Department of Chemistry, University of California at Berkeley, Berkeley, California 94720, USA
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Mass spectrometric analysis of the reactions catalyzed by l-2-haloacid dehalogenase mutants and implications for the roles of the catalytic amino acid residues. ACTA ACUST UNITED AC 2003. [DOI: 10.1016/s1381-1177(03)00097-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Konermann L, Douglas DJ. Pre-steady-state kinetics of enzymatic reactions studied by electrospray mass spectrometry with on-line rapid-mixing techniques. Methods Enzymol 2003; 354:50-64. [PMID: 12418216 DOI: 10.1016/s0076-6879(02)54005-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/27/2023]
Affiliation(s)
- Lars Konermann
- Department of Chemistry, University of Western Ontario, London, Ontario, Canada N6A 5B7
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