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1.
Bioorg Chem ; 92: 103263, 2019 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-31536953

RESUMO

α-Methylacyl-CoA racemase (AMACR; P504S) catalyses an essential step in the degradation of branched-chain fatty acids and the activation of ibuprofen and related drugs. AMACR has gained much attention as a drug target and biomarker, since it is found at elevated levels in prostate cancer and several other cancers. Herein, we report the synthesis of 2-(phenylthio)propanoyl-CoA derivatives which provided potent AMACR inhibitory activity (IC50 = 22-100 nM), as measured by the AMACR colorimetric activity assay. Inhibitor potency positively correlates with calculated logP, although 2-(3-benzyloxyphenylthio)propanoyl-CoA and 2-(4-(2-methylpropoxy)phenylthio)propanoyl-CoA were more potent than predicted by this parameter. Subsequently, carboxylic acid precursors were evaluated against androgen-dependent LnCaP prostate cancer cells and androgen-independent Du145 and PC3 prostate cancer cells using the MTS assay. All tested precursor acids showed inhibitory activity against LnCaP, Du145 and PC3 cells at 500 µM, but lacked activity at 100 µM. This is the first extensive structure-activity relationship study on the influence of side-chain interactions on the potency of novel rationally designed AMACR inhibitors.

2.
Bioorg Chem ; 92: 103264, 2019 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-31536955

RESUMO

α-Methylacyl-CoA racemase (AMACR; P504S; EC 5.1.99.4) catalyses epimerization of 2-methylacyl-CoAs and is important for the degradation of branched-chain fatty acids and the pharmacological activation of ibuprofen and related drugs. It is also a novel drug target for prostate and other cancers. However, development of AMACR as a drug target has been hampered by the difficulties in assaying enzyme activity. Consequently, reported inhibitors have been rationally designed acyl-CoA esters, which are delivered as their carboxylate prodrugs. The novel colorimetric assay for AMACR based on the elimination of 2,4-dinitrophenolate was developed for high-throughput screening and 20,387 'drug-like compounds' were screened, with a throughput of 768 compounds assayed per day. Pyrazoloquinolines and pyrazolopyrimidines were identified as novel scaffolds and investigated as AMACR inhibitors. The most potent inhibitors have IC50 values of ~2 µM. The pyrazoloquinoline inhibitor 10a displayed uncompetitive inhibition, whilst 10j displayed mixed competitive inhibition. The pyrazolopyrimidine inhibitor 11k displayed uncompetitive inhibition. This is the first report of the identification of specific drug-like small-molecule AMACR inhibitors by high-throughput screening. Pyrazoloquinolines and pyrazolopyrimidines may also be useful as inhibitors of other CoA-utilizing enzymes.

3.
Org Biomol Chem ; 17(5): 1266-1276, 2019 01 31.
Artigo em Inglês | MEDLINE | ID: mdl-30663749

RESUMO

Retama raetam is a bush which is a member of the family Fabaceae. It is used traditionally in North Africa and Saudi Arabia for the treatment of diabetes. Several flavonoids and alkaloids are already known from this plant. Chromatographic fractionation and purification led to the isolation of three new derivatives of prenylated flavones, retamasin C-E, and four new derivatives of prenylated isoflavones, retamasin F-I, in addition to two isoflavones which have not been previously reported in this plant. Particularly interesting structures included isoflavones containing 3,5-dihydro-2H-2,5-methanobenzo[e][1,4]dioxepine and 3a,8b-dihydro-7-hydroxyfuro[3,2-b]benzo[2,1-d]furan units, both of which are new amongst natural product flavonoids. Five new examples (two flavones and three isoflavones) strongly enhanced the glucose-triggered release of insulin by murine pancreatic islets and one isoflavone was a potent inhibitor of α-glucosidase. This study may rationalise the traditional medicinal use of R. raetam and provide new leads for drug design in the treatment of diabetes.


Assuntos
Fabaceae/química , Flavonoides/isolamento & purificação , Flavonoides/farmacologia , Inibidores de Glicosídeo Hidrolases/farmacologia , Insulina/metabolismo , Extratos Vegetais/farmacologia , Animais , Cromatografia Líquida de Alta Pressão , Flavonoides/química , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Arábia Saudita , Análise Espectral/métodos
4.
Bioorg Chem ; 79: 145-154, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-29751320

RESUMO

α-Methylacyl-CoA racemase (AMACR; P504S) is a promising novel drug target for prostate and other cancers. Assaying enzyme activity is difficult due to the reversibility of the 'racemisation' reaction and the difficulties in the separation of epimeric products; consequently few inhibitors have been described and no structure-activity relationship study has been performed. This paper describes the first structure-activity relationship study, in which a series of 23 known and potential rational AMACR inhibitors were evaluated. AMACR was potently inhibited (IC50 = 400-750 nM) by ibuprofenoyl-CoA and derivatives. Potency was positively correlated with inhibitor lipophilicity. AMACR was also inhibited by straight-chain and branched-chain acyl-CoA esters, with potency positively correlating with inhibitor lipophilicity. 2-Methyldecanoyl-CoAs were ca. 3-fold more potent inhibitors than decanoyl-CoA, demonstrating the importance of the 2-methyl group for effective inhibition. Elimination substrates and compounds with modified acyl-CoA cores were also investigated, and shown to be potent inhibitors. These results are the first to demonstrate structure-activity relationships of rational AMACR inhibitors and that potency can be predicted by acyl-CoA lipophilicity. The study also demonstrates the utility of the colorimetric assay for thorough inhibitor characterisation.

5.
Pharmaceuticals (Basel) ; 10(4)2017 Dec 14.
Artigo em Inglês | MEDLINE | ID: mdl-29240701

RESUMO

The 25th Conference of GP2A was held on 31 August and 1 September 2017 in Liverpool, UK, with the aim of exchange of ideas and experience, particularly amongst young medicinal chemists. Topics included bioactive compounds from plants and lichens, and design and development of drugs. Abstracts of invited lectures, proffered oral presentations, flash presentations and posters presented during the meeting are collected in this report.

6.
Oncotarget ; 8(42): 72773-72787, 2017 Sep 22.
Artigo em Inglês | MEDLINE | ID: mdl-29069825

RESUMO

Relatively little attention has been paid to ADP-ribosylated modifications of histones, especially to mono-ADP-ribosylation. As an increasing number of mono-ADP-ribosyltransferases have been identified in recent studies, the functions of mono-ADP-ribosylated proteins have aroused research interest. In particular, histones are substrates of some mono-ADP-ribosyltransferases and mono-ADP-ribosylated histone have been detected in physiological or pathological processes. In this research, arginine-117 (Arg-117; R-117) of hsitone3(H3) is identified as the a site of mono-ADP-ribosylation in colon carcinoma(the first such site to be identified); this posttranslational modification may promote the proliferation of colon carcinoma cells in vitro and in vivo. Using a point-mutant lentivirus transfection and using an activator of P300 allowed us to observe the mono-ADP-ribosylation at H3R117 and enhancement of the activity of P300 to up-regulate the level of acetylated ß-catenin, which could increase the expression of c-myc and cyclin D1.

7.
J Nat Prod ; 80(6): 1900-1908, 2017 06 23.
Artigo em Inglês | MEDLINE | ID: mdl-28581290

RESUMO

Teucrium yemense (Defl), locally known as Reehal Fatima, is a medicinal plant commonly grown in Saudi Arabia and Yemen. Phytochemical investigation of the aerial parts of T. yemense yielded six new neoclerodane diterpenoids, namely fatimanol A-E (1, 2, 3, 5, and 6) and fatimanone (4), and the known teulepicephin (7). As both the Teucrium genus and the related Lamiaceae family have previously been widely reported to possess anthelmintic and antimicrobial activities, the structural and biological characterization of the seven diterpenoids was pursued. The structures of the new compounds were elucidated from their 2D NMR and MS profiles and by comparison to related compounds. The structure of fatimanol D (5) was confirmed by X-ray crystallographic analysis. The new structures contribute to the breadth of knowledge of secondary metabolites in this genus.


Assuntos
Diterpenos/isolamento & purificação , Lamiaceae/química , Plantas Medicinais/química , Teucrium/química , Candida albicans/efeitos dos fármacos , Cristalografia por Raios X , Diterpenos/química , Escherichia coli/efeitos dos fármacos , Células Hep G2 , Humanos , Testes de Sensibilidade Microbiana , Conformação Molecular , Estrutura Molecular , Mycobacterium smegmatis/efeitos dos fármacos , Ressonância Magnética Nuclear Biomolecular , Pseudomonas aeruginosa/efeitos dos fármacos , Arábia Saudita , Staphylococcus aureus/efeitos dos fármacos
8.
Chem Commun (Camb) ; 53(37): 5087-5090, 2017 May 04.
Artigo em Inglês | MEDLINE | ID: mdl-28338138

RESUMO

α-Methylacyl-CoA racemase (AMACR; P504S) regulates branched-chain fatty acid degradation, activates Ibuprofen and is a recognised cancer drug target. A novel, facile colorimetric assay was developed based on elimination of 2,4-dinitrophenolate. The assay was used to test 5 known inhibitors, determining IC50 and Ki values, reversibility and characterizing irreversible inhibition.


Assuntos
Colorimetria/métodos , Hidroxibenzoatos/química , Nitrocompostos/química , Racemases e Epimerases/análise , Relação Dose-Resposta a Droga , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacologia , Humanos , Estrutura Molecular , Racemases e Epimerases/antagonistas & inibidores , Racemases e Epimerases/metabolismo , Relação Estrutura-Atividade
9.
J Med Chem ; 60(2): 814-820, 2017 01 26.
Artigo em Inglês | MEDLINE | ID: mdl-27983846

RESUMO

Compounds 13 and 14 were evaluated against 11 PARP isoforms to reveal that both 13 and 14 were more potent and isoform selective toward inhibiting tankyrases (TNKSs) than the "standard" inhibitor 1 (XAV939)5, i.e., IC50 = 100 pM vs TNKS2 and IC50 = 6.5 µM vs PARP1 for 14. In cellular assays, 13 and 14 inhibited Wnt-signaling, enhanced insulin-stimulated glucose uptake, and inhibited the proliferation of DLD-1 colorectal adenocarcinoma cells to a greater extent than 1.


Assuntos
Aminoquinolinas/farmacologia , Antineoplásicos/farmacologia , Glucose/metabolismo , Inibidores de Poli(ADP-Ribose) Polimerases/farmacologia , Quinazolinonas/farmacologia , Tanquirases/antagonistas & inibidores , Via de Sinalização Wnt/efeitos dos fármacos , Aminoquinolinas/síntese química , Antineoplásicos/síntese química , Linhagem Celular Tumoral , Cristalografia por Raios X , Ensaios de Seleção de Medicamentos Antitumorais , Células HEK293 , Compostos Heterocíclicos com 3 Anéis/farmacologia , Humanos , Inibidores de Poli(ADP-Ribose) Polimerases/síntese química , Isoformas de Proteínas/antagonistas & inibidores , Quinazolinonas/síntese química
10.
Eur J Med Chem ; 118: 316-27, 2016 Aug 08.
Artigo em Inglês | MEDLINE | ID: mdl-27163581

RESUMO

Tankyrases (TNKSs), members of the PARP (Poly(ADP-ribose)polymerases) superfamily of enzymes, have gained interest as therapeutic drug targets, especially as they are involved in the regulation of Wnt signalling. A series of 2-arylquinazolin-4-ones with varying substituents at the 8-position was synthesised. An 8-methyl group (compared to 8-H, 8-OMe, 8-OH), together with a 4'-hydrophobic or electron-withdrawing group, provided the most potency and selectivity towards TNKSs. Co-crystal structures of selected compounds with TNKS-2 revealed that the protein around the 8-position is more hydrophobic in TNKS-2 compared to PARP-1/2, rationalising the selectivity. The NAD(+)-binding site contains a hydrophobic cavity which accommodates the 2-aryl group; in TNKS-2, this has a tunnel to the exterior but the cavity is closed in PARP-1. 8-Methyl-2-(4-trifluoromethylphenyl)quinazolin-4-one was identified as a potent and selective inhibitor of TNKSs and Wnt signalling. This compound and analogues could serve as molecular probes to study proliferative signalling and for development of inhibitors of TNKSs as drugs.


Assuntos
Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacologia , Quinazolinonas/química , Quinazolinonas/farmacologia , Tanquirases/antagonistas & inibidores , Animais , Proliferação de Células/efeitos dos fármacos , Camundongos , Modelos Moleculares , Conformação Proteica , Relação Estrutura-Atividade , Tanquirases/química , Via de Sinalização Wnt/efeitos dos fármacos
11.
Curr Med Chem ; 22(33): 3807-29, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26429070

RESUMO

5-Aminoisoquinolin-1-one (5-AIQ) is a water-soluble inhibitor of the poly(ADPribose) polymerases (PARPs), lacking isoform-selectivity. Although of only moderate potency in vitro against PARP-1, it is highly active in many assays in cells and in models in vivo, indicating excellent uptake. Optimisation of the several synthetic sequences to 5-AIQ has led to development of a short and efficient route from 1-chloroisoquinoline. It has been used widely as a biochemical and pharmacological tool to study the effects of inhibition of the PARPs. It ameliorates the damage to cells and tissues following reperfusion of ischaemic tissue, showing significant protective activity in a rodent model of haemorrhagic shock at the remarkably low dose of 30 µg Kg(-1). Protection is also seen in models of myocardial infarction, ischaemic kidney and liver disorders, stroke and organ transplantation. Inhibition of PARP-1 by 5-AIQ causes down-regulation of the activity of NF-κB, which then down-regulates the expression of several gene products. Thus 5-AIQ has anti-inflammatory activity in vivo, through modulating the expression of cytokines and adhesion molecules. This indirect inhibition of expression is relevant in the activity of 5-AIQ in models of arthritis, Parkinson's disease, multiple sclerosis, spinal cord injury, periodontitis and inflammatory conditions of the lung. Inhibition of expression of matrix metalloproteinases and other factors gives rise to anti-angiogenic activity and to remarkable anti-metastatic activity in a mouse model. Thus, although it has been overtaken by other PARP-inhibiting drugs in the oncological clinic, 5-AIQ remains a valuable tool to study the roles of PARPs in health and in diverse diseases.


Assuntos
Isoquinolinas/química , Isoquinolinas/farmacologia , Inibidores de Poli(ADP-Ribose) Polimerases/química , Inibidores de Poli(ADP-Ribose) Polimerases/farmacologia , Poli(ADP-Ribose) Polimerases/metabolismo , Água/química , Animais , Humanos , Estrutura Molecular , Solubilidade , Relação Estrutura-Atividade
12.
Bioorg Med Chem ; 23(17): 5891-908, 2015 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-26189030

RESUMO

Tankyrases-1 and -2 (TNKS-1 and TNKS-2) have three cellular roles which make them important targets in cancer. Using NAD(+) as a substrate, they poly(ADP-ribosyl)ate TRF1 (regulating lengths of telomeres), NuMA (facilitating mitosis) and axin (in wnt/ß-catenin signalling). Using molecular modelling and the structure of the weak inhibitor 5-aminoiso quinolin-1-one, 3-aryl-5-substituted-isoquinolin-1-ones were designed as inhibitors to explore the structure-activity relationships (SARs) for binding and to define the shape of a hydrophobic cavity in the active site. 5-Amino-3-arylisoquinolinones were synthesised by Suzuki-Miyaura coupling of arylboronic acids to 3-bromo-1-methoxy-5-nitro-isoquinoline, reduction and O-demethylation. 3-Aryl-5-methylisoquinolin-1-ones, 3-aryl-5-fluoroisoquinolin-1-ones and 3-aryl-5-methoxyisoquinolin-1-ones were accessed by deprotonation of 3-substituted-N,N,2-trimethylbenzamides and quench with an appropriate benzonitrile. SAR around the isoquinolinone core showed that aryl was required at the 3-position, optimally with a para-substituent. Small meta-substituents were tolerated but groups in the ortho-positions reduced or abolished activity. This was not due to lack of coplanarity of the rings, as shown by the potency of 4,5-dimethyl-3-phenylisoquinolin-1-one. Methyl and methoxy were optimal at the 5-position. SAR was rationalised by modelling and by crystal structures of examples with TNKS-2. The 3-aryl unit was located in a large hydrophobic cavity and the para-substituents projected into a tunnel leading to the exterior. Potency against TNKS-1 paralleled potency against TNKS-2. Most inhibitors were highly selective for TNKSs over PARP-1 and PARP-2. A range of highly potent and selective inhibitors is now available for cellular studies.


Assuntos
Tanquirases/química , Sítios de Ligação , Estrutura Molecular , Relação Estrutura-Atividade
13.
Bioorg Med Chem ; 23(13): 3013-32, 2015 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-26026769

RESUMO

The tankyrases are members of the PARP superfamily; they poly(ADP-ribosyl)ate their target proteins using NAD(+) as a source of electrophilic ADP-ribosyl units. The three principal protein substrates of the tankyrases (TRF1, NuMA and axin) are involved in replication of cancer cells; thus inhibitors of the tankyrases may have anticancer activity. Using structure-based drug design and by analogy with known 3-arylisoquinolin-1-one and 2-arylquinazolin-4-one inhibitors, series of arylnaphthyridinones, arylpyridinopyrimidinones and their tetrahydro-derivatives were synthesised and evaluated in vitro. 7-Aryl-1,6-naphthyridin-5-ones, 3-aryl-2,6-naphthyridin-1-ones and 3-aryl-2,7-naphthyridin-1-ones were prepared by acid-catalysed cyclisation of the corresponding arylethynylpyridinenitriles or reaction of bromopyridinecarboxylic acids with ß-diketones, followed by treatment with NH3. The 7-aryl-1,6-naphthyridin-5-ones were methylated at 1-N and reduced to 7-aryl-1-methyl-1,2,3,4-tetrahydro-1,6-naphthyridin-5-ones. Cu-catalysed reaction of benzamidines with bromopyridinecarboxylic acids furnished 2-arylpyrido[2,3-d]pyrimidin-4-ones. Condensation of benzamidines with methyl 1-benzyl-4-oxopiperidine-3-carboxylate and deprotection gave 2-aryl-5,6,7,8-tetrahydropyrido[4,3-d]pyrimidin-4-ones, aza analogues of the known inhibitor XAV939. Introduction of the ring-N in the arylnaphthyridinones and the arylpyridopyrimidinones caused >1000-fold loss in activity, compared with their carbocyclic isoquinolinone and quinazolinone analogues. However, the 7-aryl-1-methyl-1,2,3,4-tetrahydro-1,6-naphthyridin-5-ones showed excellent inhibition of the tankyrases, with some examples having IC50=2nM. One compound (7-(4-bromophenyl)-1-methyl-1,2,3,4-tetrahydro-1,6-naphthyridin-5-one) showed 70-fold selectivity for inhibition of tankyrase-2 versus tankyrase-1. The mode of binding was explored through crystal structures of inhibitors in complex with tankyrase-2.


Assuntos
Antineoplásicos/síntese química , Desenho de Drogas , Inibidores Enzimáticos/síntese química , Naftiridinas/síntese química , Pirimidinonas/síntese química , Tanquirases/antagonistas & inibidores , Amônia/química , Antineoplásicos/química , Compostos Aza/química , Benzamidinas/química , Ácidos Carboxílicos/química , Cristalografia por Raios X , Ciclização , Inibidores Enzimáticos/química , Compostos Heterocíclicos com 3 Anéis/química , Humanos , Cetonas/química , Simulação de Acoplamento Molecular , Naftiridinas/química , Nitrilos/química , Pirimidinonas/química , Relação Estrutura-Atividade , Tanquirases/química
14.
Am J Cancer Res ; 5(2): 498-513, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25973293

RESUMO

Autophagy plays a protective role in colorectal carcinoma. Arginine ADP-ribosyltransferase 1 (ART1) is an important mono-ADP-ribose transferase, which has been shown to play a role in biological processes such as proliferation and invasion of cancer cells. Interestingly, the role of ART1 in the regulation of autophagy is still not clear. We examined effects of overexpression or knockdown of ART1 by lentiviral transfection on starvation-induced autophagy of colon carcinoma CT26 cell lines in vivo and in vitro. The formation of autophagosome was detected by electron microscopy, acridine orange staining and expression of LC3 B. The molecular contributions of ART1 in regulation of autophagy were detected by western blotting or by co-immunoprecipitation. Additionally, inhibitors were used to study further the signaling pathway of ART1 in the regulation of autophagy. CCK8 assay, plate cloning assay, soft agar assay, examination of subcutaneous transplanted carcinoma in BALB/c mice, flow cytometry and Hoechst33342 staining were used to assess survival and apoptotic ability when starvation-induced autophagy modulated by ART1 was inhibited by 3-MA. Overexpression of ART1 promoted starvation-induced autophagy, which related to increases in the expression of Rac1, NF-κB, PARP-1, LKB1 and p-AMPK and a decrease in the expression of p-P70S6K. Correspondingly, knockdown of ART1 caused the opposite effects. ART1 also interacted with integrin α7. Additionally, changes of protein expressions were further validated following inhibition of Rac1 and PARP-1 in the starvation-induced ART1-GFP CT26 cells. Inhibition of ART1-stimulated starvation-induced autophagy restrained the growth and promoted apoptosis. ART1 is thus relevant in starvation-induced autophagy in colorectal carcinoma and may play essential roles in therapeutic anticancer strategies.

15.
Bioorg Med Chem ; 23(13): 3481-9, 2015 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-25963825

RESUMO

Cyclopropabenzaindoles (CBIs) are exquisitely potent cytotoxins which bind and alkylate in the minor groove of DNA. They are not selective for cancer cells, so prodrugs are required. CBIs can be formed at physiological pH by Winstein cyclisation of 1-chloromethyl-3-substituted-5-hydroxy-2,3-dihydrobenzo[e]indoles (5-OH-seco-CBIs). Corresponding 5-NH2-seco-CBIs should also undergo Winstein cyclisation similarly. A key triply orthogonally protected intermediate on the route to 5-NH2-seco-CBIs has been synthesised, via selective monotrifluoroacetylation of naphthalene-1,3-diamine, Boc protection, electrophilic iodination, selective allylation at the trifluoroacetamide and 5-exo radical ring-closure with TEMPO. This intermediate has potential for introduction of peptide prodrug masking units (deactivating the Winstein cyclisation and cytotoxicity), addition of diverse indole-amide side-chains (enhancing non-covalent binding prior to alkylation) and use of different leaving groups (replacing the usual chlorine, allowing tuning of the rate of Winstein cyclisation). This key intermediate was elaborated into a simple model 5-NH2-seco-CBI with a dimethylaminoethoxyindole side-chain. Conversion to a bio-reactive entity and the bioactivity of this system were confirmed through DNA-melting studies (ΔTm=13°C) and cytotoxicity against LNCaP human prostate cancer cells (IC50=18nM).


Assuntos
Antineoplásicos Alquilantes/síntese química , Ciclopropanos/síntese química , DNA de Neoplasias/antagonistas & inibidores , Indóis/síntese química , Pró-Fármacos , Acetamidas , Alquilação , Antineoplásicos Alquilantes/farmacologia , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Óxidos N-Cíclicos/química , Ciclização , Ciclopropanos/farmacologia , DNA de Neoplasias/química , Desenho de Drogas , Ensaios de Seleção de Medicamentos Antitumorais , Fluoracetatos , Humanos , Concentração de Íons de Hidrogênio , Indóis/farmacologia , Modelos Moleculares , Naftalenos/química , Desnaturação de Ácido Nucleico , Relação Estrutura-Atividade
16.
Chem Commun (Camb) ; 50(91): 14164-6, 2014 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-25277991

RESUMO

α-Methylacyl-CoA racemase (AMACR; P504S) catalyses 'racemization' of 2-methylacyl-CoAs, the activation of R-ibuprofen and is a promising cancer drug target. Human recombinant AMACR 1A catalyses elimination of 3-fluoro-2-methyldecanoyl-CoAs to give E-2-methyldec-2-enoyl-CoA and fluoride anion, a previously unknown reaction. 'Racemization' of 2-methyldec-3-enoyl-CoAs was also catalysed, without double bond migration.


Assuntos
Acil Coenzima A/metabolismo , Biocatálise , Fluoretos/metabolismo , Racemases e Epimerases/metabolismo , Acil Coenzima A/química , Fluoretos/química , Humanos , Conformação Molecular , Racemases e Epimerases/química
17.
Org Biomol Chem ; 12(34): 6737-44, 2014 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-25050409

RESUMO

Mandelic acid is a chiral metabolite of the industrial pollutant styrene and is used in chemical skin peels, as a urinary antiseptic and as a component of other medicines. In humans, S-mandelic acid undergoes rapid chiral inversion to R-mandelic acid by an undefined pathway but it has been proposed to proceed via the acyl-CoA esters, S- and R-2-hydroxy-2-phenylacetyl-CoA, in an analogous pathway to that for Ibuprofen. This study investigates chiral inversion of mandelic acid using purified human recombinant enzymes known to be involved in the Ibuprofen chiral inversion pathway. Both S- and R-2-hydroxy-2-phenylacetyl-CoA were hydrolysed to mandelic acid by human acyl-CoA thioesterase-1 and -2 (ACOT1 and ACOT2), consistent with a possible role in the chiral inversion pathway. However, human α-methylacyl-CoA racemase (AMACR; P504S) was not able to catalyse exchange of the α-proton of S- and R-2-hydroxy-2-phenylacetyl-CoA, a requirement for chiral inversion. Both S- and R-2-phenylpropanoyl-CoA were epimerised by AMACR, showing that it is the presence of the hydroxy group that prevents epimerisation of R- and S-2-hydroxy-2-phenylacetyl-CoAs. The results show that it is unlikely that 2-hydroxy-2-phenylacetyl-CoA is an intermediate in the chiral inversion of mandelic acid, and that the chiral inversion of mandelic acid is via a different pathway to that of Ibuprofen and related drugs.


Assuntos
Ácidos Mandélicos/química , Palmitoil-CoA Hidrolase/química , Racemases e Epimerases/química , Acetilcoenzima A/química , Biotransformação , Humanos , Hidrólise , Ibuprofeno/química , Ibuprofeno/metabolismo , Isoenzimas/química , Ácidos Mandélicos/metabolismo , Soluções , Estereoisomerismo
18.
Phytochemistry ; 105: 186-96, 2014 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-24894362

RESUMO

Society is demanding more green chemicals from sustainable sources. Miscanthus is a potential source of platform chemicals and bioethanol through fermentation. Miscanthus sinensis (M. sinensis) has been found to contain particularly high levels of soluble phenols (hydroxycinnamates and flavonoids) which may have application in the nutraceutical, cosmetic and pharmaceutical industries. Here, we describe the first study on the identification and quantification of phenols from the leaf tissue of a bi-parental M. sinensis mapping family. Parents and progeny showed complex profiles of phenols with highly related structures which complicated characterisation of individual phenotypes. Separation of semi-purified extracts by reverse-phase liquid chromatography, coupled with detection by diode array and ESI-MS/MS, enabled distinction of different profiles of phenols. Ten hydroxycinnamates (O-cinnamoylquinic acids) and several flavones (one mono-O-glycosyl flavone, eight mono-C-glycosyl flavones, two di-C-glycosyl flavones, five O-glycosyl-C-glycosyl flavones and nine 2″-O-glycosyl-C-glycosyl flavones) were identified and quantified in leaf tissue of two hundred progeny and maternal and paternal plants during the seedling stage. Progeny exhibiting high, moderate and low amounts of hydroxycinnamates and flavonoids and both parents were selected and screened at seven months' growth to determine the abundance of these phenols at their highest biomass and compared with seedlings. Concentrations of phenols generally decreased as leaves matured. Several flavone-glycosides were identified. This technique can be used for rapid screening of plants in a mapping family to identify genotypes with high phenol content to add value in the biorefinery chain. This comparative study provides information on the content of potentially valuable compounds from readily renewable resources and possible biomarkers for identification in breeding programmes.


Assuntos
Poaceae/química , Cromatografia Líquida , Glicosídeos/análise , Luteolina/análise , Fenóis/análise , Folhas de Planta/química , Espectrometria de Massas por Ionização por Electrospray , Espectrometria de Massas em Tandem
19.
Biochem Pharmacol ; 86(11): 1621-5, 2013 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-24041740

RESUMO

Ibuprofen and related 2-arylpropanoic acid (2-APA) drugs are often given as a racemic mixture and the R-enantiomers undergo activation in vivo by metabolic chiral inversion. The chiral inversion pathway consists of conversion of the drug to the coenzyme A ester (by an acyl-CoA synthetase) followed by chiral inversion by α-methylacyl-CoA racemase (AMACR; P504S). The enzymes responsible for hydrolysis of the product S-2-APA-CoA ester to the active S-2-APA drug have not been identified. In this study, conversion of a variety of 2-APA-CoA esters by human acyl-CoA thioesterase-1 and -2 (ACOT-1 and -2) was investigated. Human recombinant ACOT-1 and -2 (ACOT-1 and -2) were both able to efficiently hydrolyse a variety of 2-APA-CoA substrates. Studies with the model substrates R- and S-2-methylmyristoyl-CoA showed that both enzymes were able to efficiently hydrolyse both of the epimeric substrates with (2R)- and (2S)- methyl groups. ACOT-1 is located in the cytosol and is able to hydrolyse 2-APA-CoA esters exported from the mitochondria and peroxisomes for inhibition of cyclo-oxygenase-1 and -2 in the endoplasmic reticulum. It is a prime candidate to be the enzyme responsible for the pharmacological action of chiral inverted drugs. ACOT-2 activity may be important in 2-APA toxicity effects and for the regulation of mitochondrial free coenzyme A levels. These results support the idea that 2-APA drugs undergo chiral inversion via a common pathway.


Assuntos
Acil Coenzima A/química , Ibuprofeno/química , Palmitoil-CoA Hidrolase/química , Tioléster Hidrolases/química , Acil Coenzima A/metabolismo , Cristalografia por Raios X , Escherichia coli/genética , Ésteres , Humanos , Hidrólise , Ibuprofeno/metabolismo , Cinética , Modelos Moleculares , Estrutura Molecular , Palmitoil-CoA Hidrolase/genética , Palmitoil-CoA Hidrolase/metabolismo , Conformação Proteica , Estereoisomerismo , Especificidade por Substrato , Tioléster Hidrolases/genética , Tioléster Hidrolases/metabolismo
20.
Org Biomol Chem ; 11(36): 6208-14, 2013 Sep 28.
Artigo em Inglês | MEDLINE | ID: mdl-23939204

RESUMO

1-Iodonaphthalene-2,4-diamines in trifluoroacetic acid/chloroform give stable Wheland-like tetrahedral cationic species observable by NMR, through an initial intramolecular protonation. Dynamic equilibria allow proton-deuterium exchange of aromatic protons and provide a mechanism for deiodination of 1-iodonaphthalene-2,4-diamines.


Assuntos
Diaminas/química , Naftalenos/química , Ácido Trifluoracético/química , Cátions/química , Clorofórmio/química , Diaminas/síntese química , Espectroscopia de Ressonância Magnética , Estrutura Molecular , Naftalenos/síntese química
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