Biochemistry Commons^™

Β-Lactam Estrogen Receptor Antagonists And A Dual-Targeting Estrogen Receptor/Tubulin Ligand, Niamh O'Boyle, Jade K. Pollock, Miriam Carr, Andrew Js Knox, Seema M. Nathwani, Shu Wang, Laura Caboni, Daniela M. Zisterer, Mary Meegan

Articles

Twelve novel β-lactams were synthesised and their antiproliferative effects and binding affinity for the predominant isoforms of the estrogen receptor (ER), ERα and ERβ, were determined. β-Lactams 23 and 26 had the strongest binding affinities for ERα (IC₅₀ values: 40 and 8 nM respectively) and ERβ (IC₅₀ values: 19 and 15 nM). β-Lactam 26 was the most potent in antiproliferative assays using MCF-7 breast cancer cells, and further biochemical analysis showed that it caused accumulation of cells in G₂/M phase (mitotic blockade) and depolymerisation of tubulin in MCF-7 cells. Compound 26 also induced apoptosis and downregulation …

Immunoproteomic Analysis Of Proteins Expressed By Two Related Pathogens, Burkholderia Multivorans And Burkholderia Cenocepacia, During Human Infection., Minu Shinoy, Ruth Dennehy, Lorraine Coleman, Stephen Carberru, Kirsten Schaffer, Máire Callaghan, Sean Doyle, Siobhan Mcclean

Articles

Burkholderia cepacia complex (Bcc) is an opportunistic bacterial pathogen that causes chronic infections in people with cystic fibrosis (CF). It is a highly antibiotic resistant organism and Bcc infections are rarely cleared from patients, once they are colonized. The two most clinically relevant species within Bcc are Burkholderia cenocepacia and Burkholderia multivorans. The virulence of these pathogens has not been fully elucidated and the virulence proteins expressed during human infection have not been identified to date. Furthermore, given its antibiotic resistance, prevention of infection with a prophylactic vaccine may represent a better alternative than eradication of an existing infection. We …

Raman Spectroscopic Analysis Of Human Skin Tissue Sections Ex-Vivo: Evaluation Of The Effects Of Tissue Processing And Dewaxing, Syed Mehmood Ali, Franck Bonnier, Ali Tfayli, Helen Lambkin, Kathleen Flynn, Vincent Mcdonagh, Claragh Healy, Thomas Lee, Fiona Lyng, Hugh Byrne

Articles

Raman spectroscopy coupled with K-means clustering analysis (KMCA) is employed to elucidate the biochemical structure of human skin tissue sections, and the effects of tissue processing. Both hand and thigh sections of human cadavers were analysed in their unprocessed and formalin fixed paraffin processed (FFPP) and subsequently dewaxed forms. In unprocessed sections, KMCA reveals clear differentiation of the stratum corneum, intermediate underlying epithelium and dermal layers for sections from both anatomical sites. The stratum corneum is seen to be relatively rich in lipidic content; the spectrum of the subjacent layers is strongly influenced by the presence of melanin, while that …

Epigenetic Regulation Of Oxysterol Formation, Steve Meaney

Articles

Oxysterols are oxygenated derivatives of cholesterol that may be formed by either enzymatic or non-enzymatic mechanisms. Expression of the genes responsible oxysterol synthesis (GROS) is known to be restricted across different tissues and cell types. Regulation of the transcription of GROS and the activity of their enzyme transcripts has been the subject of intense activity for many years. Recent studies have sought to decipher the mechanism(s) that underpin the restricted expression of the GROS. Available data indicates that epigenetic mechanisms have an important role to play in the control of the expression of GROS. In the current review we summarize …

Synthesis And Biochemical Activities Of Antiproliferative Amino Acid And Phosphate Derivatives Of Microtubule-Disrupting Beta-Lactam Combretastatins, Niamh M. O'Boyle, Lisa M. Greene, Niall O. Keely, Shu Wang, Tadhg S. Cotter, Daniela M. Zisterer, Mary J. Meegan

Articles

The synthesis and biochemical activities of novel water-soluble β-lactam analogues of combretastatin A-4 are described. The first series of compounds investigated, β-lactam phosphate esters 7a, 8a and 9a, exhibited potent antiproliferative activity and caused microtubule disruption in human breast carcinoma-derived MCF-7 cells. They did not inhibit tubulin polymerisation in vitro, indicating that biotransformation was necessary for their antiproliferative and tubulin binding effects in MCF-7 cells. The second series of compounds, β-lactam amino acid amides (including 10k and 11l) displayed potent antiproliferative activity in MCF-7 cells, disrupted microtubules in MCF-7 cells and also inhibited the polymerisation of …

Novel Cis-Restricted Β-Lactam Combretastatin A-4 Analogues Display Anti-Vascular And Anti-Metastatic Properties In Vitro, Seema M. Nathwani, Lisa M. Greene, Linda Hughes, Miriam Carr, Niamh O'Boyle, Susan Mcdonnell, Mary J. Meegan, Daniela M. Zisterer

Articles

No abstract provided.

Rna Interference Of Ctla4 In Human Leukaemia T Cells, Ralitsa Vassileva

Doctoral

The activation of naive T cells is essential for the initiation of the adaptive immunity. One promising approach to overcome immunological tolerance involves augmenting endogenous T cell-mediated immunity by interrupting the T cell down-regulatory pathways. In this project a gene therapy delivery system to overexpress small interfering RNA was used to silence the inhibitory signals induced by CTLA4. A small hairpin RNA duplex designed to silence expression of CTLA4 was successfully cloned into a plasmid. A stably transfected T cell line that is expressing constitutively the CTLA4 siRNA has been developed as a model to understand the role of CTLA4 …

Inhibition Of Burkholderia Multivorans Adhesion To Lung Epithelial Cells By Bivalent Lactosides, Ciara Wight, Rosaria Leyden, Paul V. Murphy, Máire Callaghan, Trinidad Velasco-Torrijos, Siobhan Mcclean

Articles

Burkholderia cepacia complex (Bcc) is an opportunistic pathogen in cystic fibrosis patients which is inherently resistant to antimicrobial agents. The mechanisms of attachment and pathogenesis of Bcc, a group of 17 species, are poorly understood. The most commonly identified Bcc species in newly colonised patients, Burkholderia multivorans, continues to be acquired from the environment. Development of therapies which can prevent or reduce the risk of colonization on exposure to Bcc in the environment would be a better alternative to antimicrobial agents. Previously, it has been shown that Bcc strains bound to many glycolipid receptors on lung epithelia. Using a …

Interaction Of Environmental B. Cenocepacia Strains With Cystic Fibrosis And Non-Cystic Fibrosis Bronchial Epithelial Cells In Vitro., Annamaria Bevivino, Luisa Pirone, Ruth Pilkington, Noemi Cifani, Claudia Dalmastri, Máire Callaghan, Fiorentina Ascenzioni, Siobhan Mcclean

Articles

Burkholderia cenocepacia is an important human pathogen in patients with cystic fibrosis (CF). Non-clinical reservoirs may play a role in the acquisition of infections, so it is important to evaluate the pathogenic potential of environmental B. cenocepacia isolates. In this study, we investigated the interactions of two environmental B. cenocepacia strains (Mex1 and MCII-168) with two bronchial epithelial cell lines,16HBE14o- and CFBE41o-, which have a non-CF and a CF phenotype, respectively.

The environmental strains showed a significantly lower level of invasion into both CF- and non-CF cells in comparison with the clinical B. cenocepacia LMG16656^T strain. Exposure of polarized …

Bacterial Host Interactions In Cystic Fibrosis, Máire Callaghan, Siobhan Mcclean

Articles

Chronic infection is a hallmark of cystic fibrosis (CF) and the main contributor to morbidity. Microbial infection in CF is complex, due to the number of different species that colonise the CF lung. Their colonisation is facilitated by a host response that is impaired or compromised by highly viscous mucous, zones of hypoxia and the lack of the cystic fibrosis transmembrane regulator (CFTR). Successful dominant CF pathogens combine an effective arsenal to establish infection and counter-attack the host response, together with an ability to adapt readily to an unfavourable environment. Hypermutability is common among CF pathogens facilitating adaptation and as …

The Speed Of Sound And Attenuation Of An Iec Agar-Based Tissue-Mimicking Material For High Frequency Ultrasound Applications, Chao Sun, Stephen Pye, Jacinta Browne, Anna Janeczko, Bill Ellis, Mairead Butler, Vassilis Sboros, Adrain Thomson, Mark Brewin, Charles Earnshaw, Carmel Moran

Articles

No abstract provided.

Combretazet-3 A Novel Synthetic Cis-Stable Combretastatin-A4-Azetidinone Hybrid With Enhanced Stabilityand Therapeutic Efficacy In Colon Cancer, Lisa M. Greene, Shu Wang, Niamh O'Boyle, Sandra A. Bright, Jane E. Reid, Patrick Kelly, Mary J. Meegan, Daniela M. Zisterer

Articles

In recent years an extensive series of synthetic combretastatin A-4 (CA-4)-azetidinone (β-lactam) hybrids were designed and synthesised with a view to improve the stability, therapeutic efficacy and aqueous solubility of CA-4. Lead compounds containing a 3,4,5-trimethoxy aromatic ring at position 1 and a variety of substitution patterns at positions 3 and 4 of the β-lactam ring were screened in three adenocarcinoma-derived colon cancer cell lines (CT-26, Caco-2 and the CA-4 resistant cell line, HT-29). In both CT-26 and Caco-2 cells all β-lactam analogues analysed displayed potent therapeutic efficacy within the nanomolar range. Substitution of the ethylene bridge of CA-4 with …

Differential Precipitation And Solubilization Of Proteins., Barry Ryan

Books/Book Chapters/ Proceedings

Differential protein precipitation is a rapid and economical step in protein purification and is based on exploiting the inherent physico-chemical properties of the polypeptide. Precipitation of recombinant proteins, lysed from the host cell, is commonly used to concentrate the protein of choice before further polishing steps with more selective purification columns (e.g. His-Tag, Size Exclusion etc.). Recombinant proteins can also precipitate naturally as inclusion bodies due to various influences during over-expression in the host cell. Although this phenomenon permits easier initial separation from native proteins, these inclusion bodies must carefully be differentially solubilised so as to reform functional, correctly folded …

Synthesis, Evaluation And Structural Studies Of Antiproliferative Tubulin-Targeting Azetidin-2-Ones, Niamh O'Boyle, Lisa M. Greene, Orla Bergin, Jean-Baptiste Fichet, Thomas Mccabe, David G. Lloyd, Daniela M. Zisterer, Mary J. Meegan

Articles

A series of azetidin-2-ones substituted at positions 2, 3 and 4 of the azetidinone ring scaffold were synthesised and evaluated for antiproliferative, cytotoxic and tubulin binding activity. In these compounds, the cis double bond of the vascular targeting agent combretastatin A-4 is replaced with the azetidinone ring in order to enhance the antiproliferative effects displayed by combretastatin A-4 and prevent the cis/trans isomerization that is associated with inactivation of combretastatin A-4. The series of azetidinones was synthetically accessible via the Staudinger and Reformatsky reactions. Of a diverse range of heterocyclic derivatives, 3-(2-thienyl) analogue 28 and 3-(3-thienyl) analogue 29 displayed the …

Synthesis, Biochemical And Molecular Modelling Studies Of Antiproliferative Azetidinones Causing Microtubule Disruption And Mitotic Catastrophe, Niamh O'Boyle, Miriam Carr, Lisa M. Greene, Niall O. Keely, Andrew Js Knox, Thomas Mccabe, David G. Lloyd, Daniela M. Zisterer, Mary J. Meegan

Articles

The structure-activity relationships of antiproliferative β-lactams, focusing on modifications at the 4-position of the β-lactam ring, is described. Synthesis of this series of compounds was achieved utilizing the Staudinger and Reformatsky reactions. The antiproliferative activity was assessed in MCF-7 cells, where the 4-(4-ethoxy)phenyl substituted compound 26 displayed the most potent activity with an IC₅₀ value of 0.22 μM. The mechanism of action was demonstrated to be by inhibition of tubulin. Cell exposure to combretastatin A-4 and 26 led to arrest of MCF-7 cells in the G2/M phase of the cell cycle and induction of apoptosis. Additionally, mitotic catastrophe for …

Lead Identification Of Β-Lactam And Related Imine Inhibitors Of The Molecular Caperone Heat Shock Protein 90, Niamh O'Boyle, Andrew Js Knox, Trevor P. Price, D. Clive Williams, Daniela M. Zisterer, David G. Lloyd, Mary J. Meegan

Articles

Heat shock protein 90 is an emerging target for oncology therapeutics. Inhibitors of this molecular chaperone, which is responsible for the maintenance of a number of oncogenic proteins, have shown promise in clinical trials and represent a new and exciting area in the treatment of cancer. Heat shock protein 90 inhibitors have huge structural diversity, and here we present the identification of inhibitors based on β-lactam and imine templates. β-Lactam 5 and imines 12 and 18 exhibit binding to heat shock protein 90-α with IC₅₀ values of 5.6 μM, 14.5 μM and 22.1 μM respectively. The binding affinity displayed …

Virulence Of An Emerging Respiratory Pathogen, Genus Pandoraea, In Vivo And Its Interactions With Lung Epithelial Cells, Gillian Herbert, Anne Costello, Lydia Fabunmi, Kirsten Schaffer, Kevin Kavanagh, Emma M. Caraher, Máire Callaghan, Siobhan Mcclean

Articles

Pandoraea species have emerged as opportunistic pathogens among cystic fibrosis (CF) and non-CF patients. Pandoraea pulmonicola is the predominant Pandoraea species among Irish CF patients. The objective of this study was to investigate the pathogenicity and potential mechanisms of virulence of Irish P. pulmonicola isolates and strains from other Pandoraea species. Three patients from whom the P. pulmonicola isolates were isolated have since died. The in vivo virulence of these and other Pandoraea strains was examined by determining the ability to kill Galleria mellonella larvae. The P. pulmonicola strains generally were the most virulent of the species tested, with three …

Study Of The Efficacy, Biodistribution, And Safety Profile Of Therapeutic Gutless Adenovirus Vectors As A Prelude To A Phase I Clinical Trial For Glioblastoma, Akm Ghulam Muhammad, Mariana Puntel, Marianela Candolfi, A Salem, Kader Yagiz, C Farrokhi, Kurt Kroeger, Weidong Xiong, James Curtin, Chunyan Liu, K Lawrence, Niyati Bondale, Jonathan Lerner, G Baker, David Foulad, Robert Pechnick, Donna Palmer, Philip Ng, Pedro Lowenstein, Maria Castro

Articles

Glioblastoma multiforme (GBM) is the most common and most aggressive primary brain tumor in humans. Systemic immunity against gene therapy vectors has been shown to hamper therapeutic efficacy; however, helper-dependent high-capacity adenovirus (HC-Ad) vectors elicit sustained transgene expression, even in the presence of systemic anti-adenoviral immunity. We engineered HC-Ads encoding the conditional cytotoxic herpes simplex type 1 thymidine kinase (TK) and the immunostimulatory cytokine fms-like tyrosine kinase ligand 3 (Flt3L). Flt3L expression is under the control of the regulatable Tet-ON system. In anticipation of a phase I clinical trial for GBM, we assessed the therapeutic efficacy, biodistribution, and clinical and …

Release Of Hmgb1 In Response To Pro-Apoptotic Glioma Killing Strategies: Efficacy And Neurotoxicity, Marianela Candolfi, Kader Yagiz, David Foulad, Gabrielle Alzadeh, Matthew Tesarfreund, Akm Ghulam Muhammad, Mariana Puntel, Kurt Kroeger, Chunyan Liu, Sharon Lee, James Curtin, Gwendalyn D. King, Jonathan Lerner, Katsuaki Sato, Yohei Mineharu, Weidong Xiong, Pedro R. Lowenstein, Maria Castro

Articles

Purpose In preparation for a Phase I clinical trial utilizing a combined cytotoxic/immunotherapeutic strategy using adenoviruses expressing Flt3L (Ad-Flt3L) and thymidine kinase (Ad-TK) to treat glioblastoma (GBM), we tested the hypothesis that Ad-TK+GCV would be the optimal tumor killing agent in relation to efficacy and safety when compared to other pro-apoptotic approaches. Experimental Design and Results The efficacy and neurotoxicity of Ad-TK+GCV was compared with Ads encoding the pro-apoptotic cytokines (TNF-α, TRAIL, FasL), alone or in combination with Ad-Flt3L. In rats bearing small GBMs (day 4), only Ad-TK+GCV or Ad-FasL improved survival. In rats bearing large GBMs (day 9), the …

Genetic Connections Between Neurological Disorders And Cholesterol Metabolism, Ingemar Bjorkhem, Valerio Leoni, Steve Meaney

Articles

Cholesterol is an essential component of both the peripheral and central nervous systems of mammals. Over the last decade, evidence has accumulated that disturbances in cholesterol metabolism are associated with the development of various neurological conditions. In addition to genetically defined defects in cholesterol synthesis, which will be covered in another review in this Thematic Series, defects in cholesterol metabolism (cerebrotendinous xanthomatosis) and intracellular transport (Niemann Pick Syndrome) lead to neurological disease. A subform of hereditary spastic paresis (type SPG5) and Huntington's disease are neurological diseases with mutations in genes that are of importance for cholesterol metabolism. Neurodegeneration is generally …

Synthesis And Evaluation Of Azetidinone Analogues Of Combretastatin A-4 As Tubulin Targeting Agents, Niamh O'Boyle, Miriam Carr, Lisa M. Greene, Orla Bergin, Seema M. Nathwani, Thomas Mccabe, David G. Lloyd, Daniela M. Zisterer, Mary J. Meegan

Articles

The synthesis and antiproliferative activity of a new series of rigid analogues of combretastatin A-4 are described which contain the 1,4-diaryl-2-azetidinone (β-lactam) ring system in place of the usual ethylene bridge present in the natural combretastatin stilbene products. These novel compounds are also substituted at position 3 of the β-lactam ring with an aryl ring. A number of analogues showed potent nanomolar activity in human MCF-7 and MDA-MB-231 breast cancer cell lines, displayed in vitro inhibition of tubulin polymerization and did not cause significant cytotoxicity in normal murine breast epithelial cells. 4-(4-Methoxyaryl)-substituted compound 32, 4-(3-hydroxy-4-methoxyaryl)-substituted compounds 35 and 41 and …

Purification And Properties Of Amycolatopsis Mediterranei Dsm 43304 Lipase And Its Potential In Flavour Ester Synthesis, Dharmendra Dheeman, Gary Henehan, Jesus Maria Frias

Articles

An extracellular thermostable lipase from Amycolatopsis mediterranei DSM 43304 has been purified to homogeneity using ammonium sulphate precipitation followed by anion exchange chromatography and hydrophobic interaction chromatography. This protocol resulted in 398 fold purification with 36% final recovery. The purified A. mediterranei DSM 43304 lipase (AML) has an apparent molecular mass of 33 kDa. The N-terminal sequence, AANPYERGPDPTTASIEATR, showed highest similarity to a lipase from Streptomyces exfoliatus. The values of and for p-nitrophenyl palmitate (p-NPP) under optimal temperature (60°C) and pH (8.0) conditions were 0.10 ± 0.01 mM and 2.53 ± 0.06 mmol/minmg, respectively. The purified …

Influence Of Cultivation Conditions On The Production Of A Thermostable Extracellular Lipase From Amycolatopsis Mediterranei Dsm 43304, Dharmdendra Dheeman, Jesus Maria Frias, Gary Henehan

Articles

Among several lipase producing actinomycete strains screened, Amycolatopsis mediterranei DSM 43304 was found to produce a thermostable, extracellular lipase. Culture condition and nutrient source modification studies involving carbon sources, nitrogen sources, incubation temperature and medium pH were carried out. Lipase activity of 1.37 ± 0.103 IU/ml of culture medium was obtained in 96 h at 28 °C and pH 7.5 using linseed oil and fructose as carbon sources and a combination of phytone peptone and yeast extract (5:1) as nitrogen sources. In optimal culture conditions the lipase activity was enhanced 12-fold with a 2-fold increase in lipase specific activity. The …

Hmgb1 Mediates Endogenous Tlr2 Activation And Brain Tumor Regression, James Curtin, Naiyou Liu, Marianela Candolfi, Weidong Xiong, Hikmat Assi, Kader Yagiz, Matthew Edwards, Kathrin Michelsen, Kurt Kroeger, Chunyan Liu, Akm Ghulam Muhammad, Mary Clark, Moshe Arditi, Begonya Comin-Anduix, Antoni Ribas, Pedro Lowenstein, Maria Castro

Articles

BACKGROUND: Glioblastoma multiforme (GBM) is the most aggressive primary brain tumor that carries a 5-y survival rate of 5%. Attempts at eliciting a clinically relevant anti-GBM immune response in brain tumor patients have met with limited success, which is due to brain immune privilege, tumor immune evasion, and a paucity of dendritic cells (DCs) within the central nervous system. Herein we uncovered a novel pathway for the activation of an effective anti-GBM immune response mediated by high-mobility-group box 1 (HMGB1), an alarmin protein released from dying tumor cells, which acts as an endogenous ligand for Toll-like receptor 2 (TLR2) signaling …

Transcriptional Regulation Of Cholesterol 24-Hydroxylase By Histone Deacetylase Inhibitors., Marjan Shafaati, Riona O'Driscoll, Ingemar Bjorkhem, Steve Meaney

Articles

The mechanistic basis for the tissue specific expression of cholesterol elimination pathways is poorly understood. To gain additional insight into this phenomenon we considered it of interest to investigate if epigenetic mechanisms are involved in the regulation of the brain-specific enzyme cholesterol 24-hydroxylase (CYP46A1), a key regulator of brain cholesterol elimination. We demonstrated a marked time-dependent derepression of the expression of CYP46A1, in response to treatment with the potent histone deacetylase (HDAC) inhibitor Trichostatin A. The pattern of expression of the genes in the genomic region surrounding CYP46A1 was found to be diametrically opposite in brain and liver. Intraperitoneal injection …

Treg Depletion Inhibits Efficacy Of Cancer Immunotherapy: Implications For Clinical Trials., James Curtin, Marianela Candolfi, Tamer Fakhouri, Chunyan Liu, Anderson Alden, Matthew Edwards, Pedro Lowenstein, Maria Castro

Articles

BACKGROUND: Regulatory T lymphocytes (Treg) infiltrate human glioblastoma (GBM); are involved in tumor progression and correlate with tumor grade. Transient elimination of Tregs using CD25 depleting antibodies (PC61) has been found to mediate GBM regression in preclinical models of brain tumors. Clinical trials that combine Treg depletion with tumor vaccination are underway to determine whether transient Treg depletion can enhance anti-tumor immune responses and improve long term survival in cancer patients. FINDINGS: Using a syngeneic intracrabial glioblastoma (GBM) mouse model we show that systemic depletion of Tregs 15 days after tumor implantation using PC61 resulted in a decrease in Tregs …

Turning The Gene Tap Off; Implications Of Regulating Gene Expression For Cancer Therapeutics, James Curtin, Marianela Candolfi, Weidong Xiong, Pedro Lowenstein, Maria Castro

Articles

Cancer poses a tremendous therapeutic challenge worldwide, highlighting the critical need for developing novel therapeutics. A promising cancer treatment modality is gene therapy, which is a form of molecular medicine designed to introduce into target cells genetic material with therapeutic intent. Anticancer gene therapy strategies currently used in preclinical models, and in some cases in the clinic, include proapoptotic genes, oncolytic/replicative vectors, conditional cytotoxic approaches, inhibition of angiogenesis, inhibition of growth factor signaling, inactivation of oncogenes, inhibition of tumor invasion and stimulation of the immune system. The translation of these novel therapeutic modalities from the preclinical setting to the clinic …

Regulated Expression Of Adenoviral Vectors-Based Gene Therapies: Therapeutic Expression Of Toxins And Immune-Modulators, James Curtin, Marianela Candolfi, Mariana Puntel, Weidong Xiong, Akm Ghulam Muhammad, Kurt Kroeger, Sonali Mondkar, Chunyan Liu, Niyati Bondale, Pedro Lowenstein, Maria Castro

Articles

Regulatable promoter systems allow gene expression to be tightly controlled in vivo. This is highly desirable for the development of safe, efficacious adenoviral vectors that can be used to treat human diseases in the clinic. Ideally, regulatable cassettes should have minimal gene expression in the "OFF" state, and expression should quickly reach therapeutic levels in the "ON" state. In addition, the components of regulatable cassettes should be non-toxic at physiological concentrations and should not be immunogenic, especially when treating chronic illness that requires long-lasting gene expression. In this chapter, we will describe in detail protocols to develop and validate first …

Novel Functions Of Acyl-Coa Thioesterases And Acyltransferases As Auxiliary Enzymes In Peroxisomal Lipid Metabolism., Mary Hunt, Stefan Alexson

Articles

Peroxisomes are single membrane bound organelles present in almost all eukaryotic cells, and to date have been shown to contain approximately 60 identified enzymes involved in various metabolic pathways, including the oxidation of a variety of lipids. These lipids include very long-chain fatty acids, methyl branched fatty acids, prostaglandins, bile acid precursors, and xenobiotics that are either β-oxidized or α-oxidized in peroxisomes. The recent identification of several acyl-CoA thioesterases and acyltransferases in peroxisomes has revealed their various functions in acting as auxiliary enzymes in α- and β-oxidation in this organelle. To date, 9 functional acyl-CoA thioesterases and acyltransferases have been …

The Nudix Hydrolase 7 Is An Acyl-Coa Diphosphatase Involved In Regulating Peroxisomal Coenzyme A Homeostasis., Sarah-Jayne Reilly, Veronica Tillander, Rob Ofman, Stefan Alexson, Mary Hunt

Articles

Coenzyme A (CoASH) is an obligate cofactor for lipids undergoing β-oxidation in peroxisomes. Although the peroxisomal membrane appears to be impermeable to CoASH, peroxisomes contain their own pool of CoASH. It is believed that CoASH enters peroxisomes as acyl-CoAs, but it is not known how this pool is regulated. The mouse nudix hydrolase 7 (NUDT7α) was previously identified in peroxisomes as a CoAdiphosphatase, and therefore suggested to be involved in regulation of peroxisomal CoASH levels. Here we show that mouse NUDT7α mainly acts as an acyl-CoA diphosphatase, with highest activity towards medium chain acyl-CoAs, and much lower activity with CoASH. …