51
|
Hagel JM, Krizevski R, Marsolais F, Lewinsohn E, Facchini PJ. Biosynthesis of amphetamine analogs in plants. TRENDS IN PLANT SCIENCE 2012; 17:404-412. [PMID: 22502775 DOI: 10.1016/j.tplants.2012.03.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2011] [Revised: 03/05/2012] [Accepted: 03/05/2012] [Indexed: 05/31/2023]
Abstract
Amphetamine analogs are produced by plants in the genus Ephedra and by Catha edulis, and include the widely used decongestants and appetite suppressants pseudoephedrine and ephedrine. A combination of yeast (Candida utilis or Saccharomyces cerevisiae) fermentation and subsequent chemical modification is used for the commercial production of these compounds. The availability of certain plant biosynthetic genes would facilitate the engineering of yeast strains capable of de novo pseudoephedrine and ephedrine biosynthesis. Chemical synthesis has yielded amphetamine analogs with myriad functional group substitutions and diverse pharmacological properties. The isolation of enzymes with the serendipitous capacity to accept novel substrates could allow the production of substituted amphetamines in synthetic biosystems. Here, we review the biology, biochemistry and biotechnological potential of amphetamine analogs in plants.
Collapse
Affiliation(s)
- Jillian M Hagel
- Department of Biological Sciences, University of Calgary, Calgary, AB, T2N 1N4, Canada
| | | | | | | | | |
Collapse
|
52
|
Barak Z, Chipman DM. Allosteric regulation in Acetohydroxyacid Synthases (AHASs) – Different structures and kinetic behavior in isozymes in the same organisms. Arch Biochem Biophys 2012; 519:167-74. [DOI: 10.1016/j.abb.2011.11.025] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2011] [Revised: 11/25/2011] [Accepted: 11/29/2011] [Indexed: 10/14/2022]
|
53
|
Gedi V, Yoon MY. Bacterial acetohydroxyacid synthase and its inhibitors - a summary of their structure, biological activity and current status. FEBS J 2012; 279:946-63. [DOI: 10.1111/j.1742-4658.2012.08505.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
54
|
Abstract
It is generally accepted that cyanobacteria have an incomplete tricarboxylic acid (TCA) cycle because they lack 2-oxoglutarate dehydrogenase and thus cannot convert 2-oxoglutarate to succinyl-coenzyme A (CoA). Genes encoding a novel 2-oxoglutarate decarboxylase and succinic semialdehyde dehydrogenase were identified in the cyanobacterium Synechococcus sp. PCC 7002. Together, these two enzymes convert 2-oxoglutarate to succinate and thus functionally replace 2-oxoglutarate dehydrogenase and succinyl-CoA synthetase. These genes are present in all cyanobacterial genomes except those of Prochlorococcus and marine Synechococcus species. Closely related genes occur in the genomes of some methanogens and other anaerobic bacteria, which are also thought to have incomplete TCA cycles.
Collapse
Affiliation(s)
- Shuyi Zhang
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, USA
| | | |
Collapse
|
55
|
Balakrishnan A, Paramasivam S, Chakraborty S, Polenova T, Jordan F. Solid-state nuclear magnetic resonance studies delineate the role of the protein in activation of both aromatic rings of thiamin. J Am Chem Soc 2012; 134:665-72. [PMID: 22092024 PMCID: PMC3257386 DOI: 10.1021/ja209856x] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Knowledge of the state of ionization and tautomerization of heteroaromatic cofactors when enzyme-bound is essential for formulating a detailed stepwise mechanism via proton transfers, the most commonly observed contribution to enzyme catalysis. In the bifunctional coenzyme, thiamin diphosphate (ThDP), both aromatic rings participate in catalysis, the thiazolium ring as an electrophilic covalent catalyst and the 4'-aminopyrimidine as acid-base catalyst involving its 1',4'-iminopyrimidine tautomeric form. Two of four ionization and tautomeric states of ThDP are well characterized via circular dichroism spectral signatures on several ThDP superfamily members. Yet, the method is incapable of providing information about specific proton locations, which in principle may be accessible via NMR studies. To determine the precise ionization/tautomerization states of ThDP during various stages of the catalytic cycle, we report the first application of solid-state NMR spectroscopy to ThDP enzymes, whose large mass (160,000-250,000 Da) precludes solution NMR approaches. Three de novo synthesized analogues, [C2,C6'-(13)C(2)]ThDP, [C2-(13)C]ThDP, and [N4'-(15)N]ThDP used with three enzymes revealed that (a) binding to the enzymes activates both the 4'-aminopyrimidine (via pK(a) elevation) and the thiazolium rings (pK(a) suppression); (b) detection of a pre-decarboxylation intermediate analogue using [C2,C6'-(13)C(2)]ThDP, enables both confirmation of covalent bond formation and response in 4'-aminopyrimidine ring's tautomeric state to intermediate formation, supporting the mechanism we postulate; and (c) the chemical shift of bound [N4'-(15)N]ThDP provides plausible models for the participation of the 1',4'-iminopyrimidine tautomer in the mechanism. Unprecedented detail is achieved about proton positions on this bifunctional coenzyme on large enzymes in their active states.
Collapse
Affiliation(s)
| | | | | | - Tatyana Polenova
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE
| | - Frank Jordan
- Department of Chemistry, Rutgers University, Newark, NJ 07102
| |
Collapse
|
56
|
Schreiner PR, Reisenauer HP, Ley D, Gerbig D, Wu CH, Allen WD. Methylhydroxycarbene: Tunneling Control of a Chemical Reaction. Science 2011; 332:1300-3. [PMID: 21659600 DOI: 10.1126/science.1203761] [Citation(s) in RCA: 238] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- Peter R Schreiner
- Institute of Organic Chemistry, Justus-Liebig University, Heinrich-Buff-Ring 58, D-35392 Giessen, Germany.
| | | | | | | | | | | |
Collapse
|
57
|
Jaña G, Jiménez V, Villà-Freixa J, Prat-Resina X, Delgado E, Alderete JB. A QM/MM study on the last two steps of the catalytic cycle of acetohydroxyacid synthase. COMPUT THEOR CHEM 2011. [DOI: 10.1016/j.comptc.2011.02.030] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
|
58
|
Invasion Age and Invader Removal Alter Species Cover and Composition at the Suisun Tidal Marsh, California, USA. DIVERSITY 2011. [DOI: 10.3390/d3020235] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
|
59
|
Vyazmensky M, Steinmetz A, Meyer D, Golbik R, Barak Z, Tittmann K, Chipman DM. Significant Catalytic Roles for Glu47 and Gln 110 in All Four of the C−C Bond-Making and -Breaking Steps of the Reactions of Acetohydroxyacid Synthase II. Biochemistry 2011; 50:3250-60. [DOI: 10.1021/bi102051h] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Maria Vyazmensky
- Ben-Gurion University of the Negev, Department of Life Sciences, Beer-Sheva 84105, Israel
| | - Andrea Steinmetz
- Georg-August University Göttingen, Albrecht-von-Haller-Institute and Göttingen Centre for Molecular Biosciences, Ernst-Caspari-Haus, Department of Bioanalytics, Justus-von-Liebig Weg 11, 37077 Göttingen, Germany
- Martin-Luther University Halle-Wittenberg, Institute for Biochemistry and Biotechnology, Kurt-Mothes-Strasse 3, 06120 Halle/Saale, Germany
| | - Danilo Meyer
- Georg-August University Göttingen, Albrecht-von-Haller-Institute and Göttingen Centre for Molecular Biosciences, Ernst-Caspari-Haus, Department of Bioanalytics, Justus-von-Liebig Weg 11, 37077 Göttingen, Germany
- Martin-Luther University Halle-Wittenberg, Institute for Biochemistry and Biotechnology, Kurt-Mothes-Strasse 3, 06120 Halle/Saale, Germany
| | - Ralph Golbik
- Martin-Luther University Halle-Wittenberg, Institute for Biochemistry and Biotechnology, Kurt-Mothes-Strasse 3, 06120 Halle/Saale, Germany
| | - Ze'ev Barak
- Ben-Gurion University of the Negev, Department of Life Sciences, Beer-Sheva 84105, Israel
| | - Kai Tittmann
- Georg-August University Göttingen, Albrecht-von-Haller-Institute and Göttingen Centre for Molecular Biosciences, Ernst-Caspari-Haus, Department of Bioanalytics, Justus-von-Liebig Weg 11, 37077 Göttingen, Germany
- Martin-Luther University Halle-Wittenberg, Institute for Biochemistry and Biotechnology, Kurt-Mothes-Strasse 3, 06120 Halle/Saale, Germany
| | - David M. Chipman
- Ben-Gurion University of the Negev, Department of Life Sciences, Beer-Sheva 84105, Israel
| |
Collapse
|
60
|
Karanth NM, Sarma SP. 1H, 13C, 15N assignments of the dimeric regulatory subunit (ilvN) of the E. coli AHAS I. BIOMOLECULAR NMR ASSIGNMENTS 2010; 4:131-133. [PMID: 20383786 DOI: 10.1007/s12104-010-9225-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2010] [Accepted: 03/30/2010] [Indexed: 05/29/2023]
Abstract
Acetohydroxyacid synthase (AHAS) is an enzyme involved in the biosynthesis of the branched chain amino acids viz, valine, leucine and isoleucine. The activity of this enzyme is regulated through feedback inhibition by the end products of the pathway. Here we report the backbone and side-chain assignments of ilvN, the 22 kDa dimeric regulatory subunit of E. coli AHAS isoenzyme I, in the valine bound form. Detailed analysis of the structure of ilvN and its interactions with the catalytic subunit of E. coli AHAS I will help in understanding the mechanism of activation and regulation of the branched chain amino acid biosynthesis.
Collapse
Affiliation(s)
- N Megha Karanth
- Lab No. 207, Molecular Biophysics Unit, Indian Institute of Science, Bangalore, 560012, India
| | | |
Collapse
|
61
|
Jaña G, Jiménez V, Villà-Freixa J, Prat-Resina X, Delgado E, Alderete J. Computational study on the carboligation reaction of acetohidroxyacid synthase: new approach on the role of the HEThDP- intermediate. Proteins 2010; 78:1774-88. [PMID: 20225259 DOI: 10.1002/prot.22693] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Acetohydroxyacid synthase (AHAS) is a thiamin diphosphate dependent enzyme that catalyses the decarboxylation of pyruvate to yield the hydroxyethyl-thiamin diphosphate (ThDP) anion/enamine intermediate (HEThDP(-)). This intermediate reacts with a second ketoacid to form acetolactate or acetohydroxybutyrate as products. Whereas the mechanism involved in the formation of HEThDP(-) from pyruvate is well understood, the role of the enzyme in controlling the carboligation reaction of HEThDP(-) has not been determined yet. In this work, molecular dynamics (MD) simulations were employed to identify the aminoacids involved in the carboligation stage. These MD studies were carried out over the catalytic subunit of yeast AHAS containing the reaction intermediate (HEThDP(-)) and a second pyruvate molecule. Our results suggest that additional acid-base ionizable groups are not required to promote the catalytic cycle, in contrast with earlier proposals. This finding leads us to postulate that the formation of acetolactate relies on the acid-base properties of the HEThDP(-) intermediate itself. PM3 semiempirical calculations were employed to obtain the energy profile of the proposed mechanism on a reduced model of the active site. These calculations confirm the role of HEThDP(-) intermediate as the ionizable group that promotes the carboligation and product formation steps of the catalytic cycle.
Collapse
Affiliation(s)
- Gonzalo Jaña
- Grupo de Química Teórica y Computacional, Facultad de Ciencias Químicas, Universidad de Concepción, Casilla 160-C, Concepción, Chile
| | | | | | | | | | | |
Collapse
|
62
|
de Carvalho LPS, Zhao H, Dickinson CE, Arango NM, Lima CD, Fischer SM, Ouerfelli O, Nathan C, Rhee KY. Activity-based metabolomic profiling of enzymatic function: identification of Rv1248c as a mycobacterial 2-hydroxy-3-oxoadipate synthase. ACTA ACUST UNITED AC 2010; 17:323-32. [PMID: 20416504 DOI: 10.1016/j.chembiol.2010.03.009] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2010] [Revised: 03/01/2010] [Accepted: 03/11/2010] [Indexed: 12/24/2022]
Abstract
Activity based metabolomic profiling (ABMP) allows unbiased discovery of enzymatic activities encoded by genes of unknown function, and applies liquid-chromatography mass spectrometry (LC-MS) to analyze the impact of a recombinant enzyme on the homologous cellular extract as a physiologic library of potential substrates and products. The Mycobacterium tuberculosis protein Rv1248c was incompletely characterized as a thiamine diphosphate-dependent alpha-ketoglutarate decarboxylase. Here, recombinant Rv1248c catalyzed consumption of alpha-ketoglutarate in a mycobacterial small molecule extract with matched production of 5-hydroxylevulinate (HLA) in a reaction predicted to require glyoxylate. As confirmed using pure substrates by LC-MS, (1)H-NMR, chemical trapping, and intracellular metabolite profiling, Rv1248c catalyzes C-C bond formation between the activated aldehyde of alpha-ketoglutarate and the carbonyl of glyoxylate to yield 2-hydroxy-3-oxoadipate (HOA), which decomposes to HLA. Thus, Rv1248c encodes an HOA synthase.
Collapse
Affiliation(s)
- Luiz Pedro S de Carvalho
- Department of Microbiology and Immunology, Weill Cornell Medical College, 1300 York Avenue, New York, NY 10065, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
63
|
Chen Y, Hoehenwarter W, Weckwerth W. Comparative analysis of phytohormone-responsive phosphoproteins in Arabidopsis thaliana using TiO2-phosphopeptide enrichment and mass accuracy precursor alignment. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2010; 63:573-83. [PMID: 20374526 DOI: 10.1111/j.1365-313x.2010.04261.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Protein phosphorylation/dephosphorylation is a central post-translational modification in plant hormone signaling, but little is known about its extent and function. Although pertinent protein kinases and phosphatases have been predicted and identified for a variety of hormone responses, classical biochemical approaches have so far revealed only a few candidate proteins and even fewer phosphorylation sites. Here we performed a global quantitative analysis of the Arabidopsis phosphoproteome in response to a time course of treatments with various plant hormones using phosphopeptide enrichment and subsequent mass accuracy precursor alignment (MAPA). The use of three time points, 1, 3 and 6 h, in combination with five phytohormone treatments, abscisic acid (ABA), indole-3-acetic acid (IAA), gibberellic acid (GA), jasmonic acid (JA) and kinetin, resulted in 324,000 precursor ions from 54 LC-Orbitrap-MS analyses quantified and aligned in a data matrix with the dimension of 6000 x 54 using the ProtMax algorithm. To dissect the phytohormone responses, multivariate principal/independent components analysis was performed. In total, 152 phosphopeptides were identified as differentially regulated; these phosphopeptides are involved in a wide variety of signaling pathways. New phosphorylation sites were identified for ABA response element binding factors that showed a specific increase in response to ABA. New phosphorylation sites were also found for RLKs and auxin transporters. We found that different hormones regulate distinct amino acid residues of members of the same protein families. In contrast, tyrosine phosphorylation of the G alpha subunit appeared to be a common response for multiple hormones, demonstrating global cross-talk among hormone signaling pathways.
Collapse
Affiliation(s)
- Yanmei Chen
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam-Golm, Germany
| | | | | |
Collapse
|
64
|
Steinmetz A, Vyazmensky M, Meyer D, Barak Z, Golbik R, Chipman DM, Tittmann K. Valine 375 and Phenylalanine 109 Confer Affinity and Specificity for Pyruvate as Donor Substrate in Acetohydroxy Acid Synthase Isozyme II from Escherichia coli. Biochemistry 2010; 49:5188-99. [DOI: 10.1021/bi100555q] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Andrea Steinmetz
- Albrecht-von-Haller-Institute and Göttingen Centre for Molecular Biosciences, Ernst-Caspari-Haus, Department of Bioanalytics, Georg-August University Göttingen, Justus-von-Liebig Weg 11, 37077 Göttingen, Germany
| | - Maria Vyazmensky
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel
| | - Danilo Meyer
- Albrecht-von-Haller-Institute and Göttingen Centre for Molecular Biosciences, Ernst-Caspari-Haus, Department of Bioanalytics, Georg-August University Göttingen, Justus-von-Liebig Weg 11, 37077 Göttingen, Germany
| | - Ze′ev Barak
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel
| | - Ralph Golbik
- Institute for Biochemistry and Biotechnology, Martin-Luther University Halle-Wittenberg, Kurt-Mothes-Strasse 3, 06120 Halle/Saale, Germany
| | - David M. Chipman
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel
| | - Kai Tittmann
- Albrecht-von-Haller-Institute and Göttingen Centre for Molecular Biosciences, Ernst-Caspari-Haus, Department of Bioanalytics, Georg-August University Göttingen, Justus-von-Liebig Weg 11, 37077 Göttingen, Germany
| |
Collapse
|
65
|
Huang X, He J, Sun XF, Sun JQ, Li YF, Shen JJ, Li SP. Characterization and molecular mechanism of a naturally occurring metsulfuron-methyl resistant strain of Pseudomonas aeruginosa. World J Microbiol Biotechnol 2009. [DOI: 10.1007/s11274-009-0199-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
|
66
|
Shaanan B, Chipman DM. Reaction mechanisms of thiamin diphosphate enzymes: new insights into the role of a conserved glutamate residue. FEBS J 2009; 276:2447-53. [DOI: 10.1111/j.1742-4658.2009.06965.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
|
67
|
|
68
|
Kluger R, Rathgeber S. Catalyzing separation of carbon dioxide in thiamin diphosphate-promoted decarboxylation. FEBS J 2008; 275:6089-100. [DOI: 10.1111/j.1742-4658.2008.06739.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
69
|
Souza TC, Josa D, Ramalho TC, Caetano MS, da Cunha EF. Molecular modelling ofMycobacterium tuberculosisacetolactate synthase catalytic subunit and its molecular docking study with inhibitors. MOLECULAR SIMULATION 2008. [DOI: 10.1080/08927020802129974] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
|
70
|
Kluger R, Tittmann K. Thiamin diphosphate catalysis: enzymic and nonenzymic covalent intermediates. Chem Rev 2008; 108:1797-833. [PMID: 18491870 DOI: 10.1021/cr068444m] [Citation(s) in RCA: 216] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Ronald Kluger
- Davenport Laboratories, Department of Chemistry, University of Toronto, Toronto, Ontario M5S 3H6 Canada.
| | | |
Collapse
|
71
|
Duggleby RG, McCourt JA, Guddat LW. Structure and mechanism of inhibition of plant acetohydroxyacid synthase. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2008; 46:309-24. [PMID: 18234503 DOI: 10.1016/j.plaphy.2007.12.004] [Citation(s) in RCA: 188] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2007] [Indexed: 05/04/2023]
Abstract
Plants and microorganisms synthesize valine, leucine and isoleucine via a common pathway in which the first reaction is catalysed by acetohydroxyacid synthase (AHAS, EC 2.2.1.6). This enzyme is of substantial importance because it is the target of several herbicides, including all members of the popular sulfonylurea and imidazolinone families. However, the emergence of resistant weeds due to mutations that interfere with the inhibition of AHAS is now a worldwide problem. Here we summarize recent ideas on the way in which these herbicides inhibit the enzyme, based on the 3D structure of Arabidopsis thaliana AHAS. This structure also reveals important clues for understanding how various mutations can lead to herbicide resistance.
Collapse
Affiliation(s)
- Ronald G Duggleby
- RDBiotech, 22 Parklands Boulevard, Little Mountain, Queensland 4551, Australia.
| | | | | |
Collapse
|
72
|
Boumba VA, Ziavrou KS, Vougiouklakis T. Biochemical pathways generating post-mortem volatile compounds co-detected during forensic ethanol analyses. Forensic Sci Int 2007; 174:133-51. [PMID: 17452087 DOI: 10.1016/j.forsciint.2007.03.018] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2007] [Revised: 03/13/2007] [Accepted: 03/21/2007] [Indexed: 11/23/2022]
Abstract
In this contribution are presented the fermentations of the main substrates present in a decaying corpse, namely carbohydrates, amino acids, glycerol and fatty acids, generating the post-mortem volatile compounds that could be detected along with ethanol during the forensic ethanol analysis. The available literature (preferably reviews) on microbial metabolic pathways (enzymes, substrates, conditions) that are implicated in the formation of these volatiles has been reviewed. The microbial formation of the following volatiles is supported by the presented biochemical data: ethanol, acetaldehyde, acetone, 2-propanol, 1-propanol, 1-butanol, isobutanol, isoamyl alcohol, d-amyl alcohol, acetate, propionate, butyrate, isobutyrate and ethyl esters (mainly ethyl acetate). The extracted information was correlated with the existing forensic literature on the post-mortem detected volatiles. The significance of the microbial produced volatiles on the selection of an appropriate internal standard for the ethanol analysis has been considered. Finally, the possible contribution of the presence of volatiles in the interpretation of ethanol analysis results in post-mortem cases is discussed.
Collapse
Affiliation(s)
- Vassiliki A Boumba
- Department of Forensic Medicine and Toxicology, Medical School, University of Ioannina, 45110 Ioannina, Greece.
| | | | | |
Collapse
|
73
|
McCourt JA, Duggleby RG. Acetohydroxyacid synthase and its role in the biosynthetic pathway for branched-chain amino acids. Amino Acids 2006; 31:173-210. [PMID: 16699828 DOI: 10.1007/s00726-005-0297-3] [Citation(s) in RCA: 171] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2005] [Accepted: 12/09/2005] [Indexed: 11/25/2022]
Abstract
The branched-chain amino acids are synthesized by plants, fungi and microorganisms, but not by animals. Therefore, the enzymes of this pathway are potential target sites for the development of antifungal agents, antimicrobials and herbicides. Most research has focused upon the first enzyme in this biosynthetic pathway, acetohydroxyacid synthase (AHAS) largely because it is the target site for many commercial herbicides. In this review we provide a brief overview of the important properties of each enzyme within the pathway and a detailed summary of the most recent AHAS research, against the perspective of work that has been carried out over the past 50 years.
Collapse
Affiliation(s)
- J A McCourt
- School of Molecular and Microbial Sciences, University of Queensland, Brisbane, Australia
| | | |
Collapse
|