Enzymes and Coenzymes Commons^™

Effects Of Normothermic Hepatic Ischemia–Reperfusion Injury On The Hepatic Disposition Of Arachidonic Acid And Its Cytochrome P450-Generated Metabolites In Rats, Vindhya Edpuganti, Reza Mehvar

Pharmacy Faculty Articles and Research

Purpose

Cytochrome P450 (P450) metabolites of arachidonic acid (AA) are potential therapeutic targets in ischemia–reperfusion (IR) injury, yet their disposition and actions in hepatic IR are unknown. Cellular AA and its P450 metabolites are primarily bound to lipid membranes, resulting in negligible free concentrations. This study investigates how hepatic IR injury impacts the disposition of free AA and its major P450 metabolites in rats.

Methods

Rats underwent 60 min of partial (70%) ischemia or sham surgery, followed by 5 min, 3 h, or 24 h of reperfusion. The effects of IR injury on free concentrations of AA and its major …

Optimizing Itpa R178c Assays Via Hplc, Jared J. Reisnouer, Wally D. Pines

2026 Symposium

Two of the major nucleotide bases in DNA and RNA (Adenine and Guanine) are derived from the purine Inosine Monophosphate (IMP). IMP may occasionally form the noncanonical nucleotide Inosine Triphosphate (ITP) within the cell and become incorporated into DNA during replication, leading to potentially lethal errors. To combat this, human cells produce the “housekeeping” enzyme Inosine Triphosphatase (ITPA) to revert ITP to IMP. A mutation of this protein that replaces the 178th amino acid Arginine with Cysteine (R178C) is associated with a fatal infantile encephalopathy. Previous assessments of enzyme-substrate binding and catalysis for ITPA variants have been run at a …

Protein Allostery Probed By Ligands Across Sites, Virgil A. Woods

Dissertations, Theses, and Capstone Projects

Allostery is a pervasive regulatory principle throughout biology, yet the structural pathways by which distal inputs alter active‑site chemistry within protein structures remain incompletely defined and exploited. This dissertation uses protein tyrosine phosphatase 1B (PTP1B) as a tractable model to map those pathways with complementary experimental and computational tools. I integrate high‑resolution hydrogen-deuterium exchange mass spectrometry (HDX-MS), room-temperature crystallography, NMR, steady-state kinetics, crystallographic pseudo-ensembles, and machine-learning-guided ligand discovery. The working premise is that regulation reflects redistribution within a conformational ensemble rather than a binary switch. That orthogonal perturbations by small molecules, mutations, and protein partners can be used to both …

Investigation Of Aldehyde Oxidase Inhibition By Clopidogrel And Its Thiol Metabolite, Rachel Crouch, Merna Kamal, Hilina Woldeamanuel

Student Scholar Symposium

Aldehyde oxidase (AO) is an enzyme that metabolizes drugs containing aromatic azaheterocycles. Small thiol-containing molecules have been reported to inactivate AO. Clopidogrel is an antiplatelet agent used to treat cardiovascular diseases. Clopidogrel is a prodrug that is bioactivated in vivo by cytochrome P450 enzymes CYP3A4 and CYP2C19 into a thiol metabolite. Our research aims to explore whether the clopidogrel thiol metabolite can inhibit AO, leading to potential drug-drug interactions when co-administered with other drugs that are metabolized by AO. In order to determine whether the prodrug clopidogrel and/or its thiol metabolite inhibit AO, O6-benzylguanine (AO substrate) was incubated with human …

Increased Intermembrane Space [Ca2+] Drives Mitochondrial Structural Damage In Cpvt, Shanna Hamilton, Radmila Terentyeva, Roland Veress, Fruzsina Perger, Zuzana Nichtova, Mark Bannister, Jinxi Wang, Sage Quiggle, Rachel Battershell, Matthew Gorr, Sandor Györke, Bum-Rak Choi, Christopher George, Andriy Belevych, György Csordás, Dmitry Terentyev

Department of Pathology, Anatomy, and Cell Biology Faculty Papers

BACKGROUND: Mitochondrial dysfunction caused by abnormally high RyR2 (ryanodine receptor) activity is a common finding in cardiovascular diseases. Mechanisms linking RyR2 gain of function with mitochondrial remodeling remain elusive. We hypothesized that RyR2 hyperactivity in cardiac disease increases [Ca 2+ ] in the mitochondrial intermembrane space (IMS) and activates the Ca 2+ -sensitive protease calpain, driving remodeling of mitochondrial cristae architecture through cleavage of structural protein OPA1 (optic atrophy protein 1).

METHODS: We generated a highly arrhythmogenic rat model of catecholaminergic polymorphic ventricular tachycardia, induced by RyR2 gain-of-function mutation S2236L(Ser2336Leu)(+/-) . We created a new biosensor to measure IMS-[Ca2+ ] …

Protein-Protein Interaction–Interfering Peptide Rescues Dysregulated Nmda Receptor Signaling, Robert E. Featherstone, Hongbin Li, Ameet S. Sengar, Karin E. Borgmann-Winter, Olya Melnychenko, Lindsey M. Crown, Ray L. Gifford, Felix Amirfathi, Anamika Banerjee, Aivi Tran, Krishna Parekh, Margaret Heller, Wenyu Zhang, Robert J. Gallop, Adam D. Marc, Pragya Komal, Michael W. Salter, Steven J. Siegel, Chang-Gyu Hahn

Farber Institute for Neuroscience Faculty Papers

The complex and heterogeneous genetic architecture of neuropsychiatric illnesses compels us to look beyond individual risk genes for therapeutic strategies and target the interactive dynamics and convergence of their protein products. A mechanistic substrate for convergence of synaptic neuropsychiatric risk genes are protein-protein interactions (PPIs) in the N-methyl-D-aspartate receptor (NMDAR) complex. NMDAR hypofunction in schizophrenia is associated with hypoactivity of Src kinase, resulting from convergent alterations in PPIs of Src with its partners. Of these, the association of Src with PSD-95, which inhibits the activity of this kinase in the NMDAR complex, is known to be increased in schizophrenia. Here, …

Dna Extrusion Size Determines Pathway Choice During Cag Repeat Expansion, Mayuri Bhatia, Ashutosh S. Phadte, Anna Lakhina, Anthony R. Monte Carloi Iii, Sarah Barndt, Anna Pluciennik

Department of Biochemistry and Molecular Biology Faculty Papers

DNA triplet repeat expansion causes several primarly neurological disorders like Huntington's disease, myotonic dystrophy type 1, and fragile-X related disorders. There is general consensus that recognition of extrahelical extrusions or hairpin-loop structures (formed by strand slippage) by the DNA mismatch repair protein MutSβ leads to repeat expansion by a mutagenic process. By contrast, the FAN1 nuclease attenuates triplet repeat expansion, the molecular basis of which was explained by our recent finding that FAN1 nuclease cleaves and initiates removal of extrahelical extrusions. Here we show that extrusions containing two or more triplet repeats are subject to recognition and processing by either …

Setdb1 Is Critically Required For Uveal Melanoma Growth And Represents A Promising Therapeutic Target, Imène Krossa, Céline Pisibon, Yann Cheli, Karine Bille, Mélanie Dalmasso, Sabah Hamadat, Chrystel Husser, Marie Irondelle, Julien Cherfils-Vicini, Frédéric Soysouvanh, Sacha Nahon-Esteve, Arnaud Martel, Sandra Lassalle, Jean-Pierre Caujolle, Célia Maschi, Stéphanie Baillif, Dan Hasson, Saul Carcamo, Andrerw E. Aplin, Irwin Davidson, Emily Bernstein, Valeria Naim, Robert Ballotti, Corine Bertolotto, Thomas Strub

Department of Pharmacology, Physiology, and Cancer Biology Faculty Papers

Metastatic uveal melanomas are highly resistant to all existing treatments. To identify actionable vulnerabilities, we conducted a CRISPR-Cas9 knockout screen using a library composed of chromatin regulators. We revealed that the lysine methyltransferase, SETDB1, plays a critical role in metastatic uveal melanoma cell proliferation and survival. Functionally, SETDB1 deficiency induces a DNA damage response, senescence-like state and growth arrest. Knockdown of SETDB1 is associated with a decreased expression of genes related to replication and cell cycle. Moreover, deficiency in CDC6, an essential regulator of DNA replication, phenocopies SETDB1 inhibition. Using a pre-clinical model, we further demonstrated that anti-SETDB1 therapy impairs …

Reaction Control Mechanism In Deoxyuridine 5'-Triphosphate Nucleotidohydrolase, Aaron Delay

School of Biological Sciences: Dissertations, Theses, and Student Research

Deoxyuridine 5'-triphosphate nucleotidohydrolase (dUTPase) is an enzyme involved in the pyrimidine biosynthesis pathway, a key component of cellular DNA metabolism. It regulates intracellular uracil carrying triphosphate levels by hydrolyzing dUTP, thereby providing a substrate for thymidylate synthase (TS). The effective inhibition of dUTPase is expected to enhance TS-targeted chemotherapy by promoting thymine-less apoptosis.

Although the reaction mechanism of dUTPase has been studied, the human nuclear homotrimeric form remains complex, as all three subunits cooperatively form a single active site. As a result, the detailed molecular dynamics of its catalysis are still not fully understood. In this study, I investigated the …

The Loss Of Opa1 Accelerates Intervertebral Disc Degeneration And Osteoarthritis In Aged Mice, Vedavathi Madhu, Miriam Hernandaz-Meadows, Ashley Coleman, Kimheak Sao, Kameron Inguito, Owen Haslam, Paige Boneski, Hiromi Sesaki, Ruteja Barve, John Collins, Makarand Risbud

Department of Orthopaedic Surgery Faculty Papers

Recent studies have highlighted the importance of mitochondria in NP cells and articular chondrocyte health. Since the understanding of mechanisms governing mitochondrial dynamics in these tissues is lacking, we investigated the role of OPA1, a mitochondrial fusion protein, in their homeostasis. OPA1 knockdown in NP cells altered mitochondrial size and cristae shape and increased the oxygen consumption rate. OPA1 governed the morphology of multiple organelles, including peroxisomes, early endosomes and cis-Golgi and loss resulted in the dysregulation of autophagy. Metabolic profiling and

Abstract 2587 Recombinant Expression And Purification Of A. Vinelandii Cown In E. Coli, Julie Takei, Cedric P. Owens, Katie Sanders, Neeraja Gajendran

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

The goal of this project is to study the protein CowN in the diazotroph Azotobacter vinelandii (Av) in comparison to CowN in Gluconacetobacter diazotrophicus (Gd). Nitrogenase is an enzyme that catalyzes the reduction of nitrogen gas into ammonia in diazotrophic bacteria. In many diazotrophs, the protein CowN prevents nitrogenase inhibition from the environmental gas carbon monoxide (CO). Previous work studied CowN in the diazotroph G. diazotrophicus. In G. diazotrophicus, CowN binds to nitrogenase and weakens CO binding to its active site. The mechanism of CowN has only been investigated in G. diazotrophicus. Thus, we are interested in determining if CowN's …

Sirt6 Deficiency Promotes Senescence And Age-Associated Intervertebral Disc Degeneration In Mice, Pranay Ramteke, Bahiyah Watson, Mallory Toci, Victoria Tran, Shira N Johnston, Maria Tsingas, Ruteja Barve, Ramkrishna Mitra, Richard Loeser, John Collins, Makarand Risbud

Department of Orthopaedic Surgery Faculty Papers

Intervertebral disc degeneration is a major risk factor contributing to chronic low back and neck pain. While the etiological factors for disc degeneration vary, age is still one of the most important risk factors. Recent studies have shown the promising role of SIRT6 in mammalian aging and skeletal tissue health, however its role in the intervertebral disc health remains unexplored. We investigated the contribution of SIRT6 to disc health by studying the age-dependent spinal phenotype of mice with conditional deletion of Sirt6 in the disc (Acan^CreERT2; Sirt6^fl/fl). Histological studies showed a degenerative phenotype in knockout mice …

Targeting Bard1 Suppresses A Myc-Dependent Transcriptional Program And Tumor Growth In Pancreatic Ductal Adenocarcinoma, Sohum Patel, Eleanor Jenkins, Rutuj P. Kusurkar, Sherry Lee, Wei Jiang, Avinoam Nevler, Matthew Mccoy, Michael J. Pishvaian, Rosalie C. Sears, Jonathan R. Brody, Charles J. Yeo, Aditi Jain

Department of Surgery Faculty Papers

Pancreatic ductal adenocarcinoma (PDAC) remains one of the deadliest cancers demanding better and more effective therapies. BARD1 or BRCA1-Associated -Ring Domain-1 plays a pivotal role in homologous recombination repair (HRR). However, its function and the underlying molecular mechanisms in PDAC are still not fully elucidated. Here, we demonstrate that BARD1 is overexpressed in PDAC and its genetic inhibition suppresses c-Myc and disrupts c-Myc dependent transcriptional program. Mechanistically, BARD1 stabilizes c-Myc through ubiquitin-proteasome system by regulating FBXW7. Importantly, targeting BARD1 using either siRNAs or CRISPR/Cas9 deletion blocks PDAC growth in vitro and in vivo, without any signs of toxicity to mice. …

Assessing The Behavioral Impact Of Pyridostigmine Bromide In Rats, Noah A. Martin

Honors Theses

Pyridostigmine bromide (PB) is an organophosphate (OP) nerve agent prophylactic used to protect warfighters against chemical warfare agents. OPs inhibit the neural enzyme acetylcholinesterase (AChE) in the brain. This leads to the buildup of acetylcholine, causing respiratory failure, seizures, and death. PB functions by inhibiting ~30% of peripheral AChE temporarily, protecting the enzymes so that the body is able to restore sufficient cholinergic function post-exposure. PB does not cross the blood-brain barrier, though it may still indirectly affect toxicity in the brain due to repeated AChE inhibition throughout treatment, or by inhibition of non-target ChE’s in the blood. The aim …

Domain Communication In Bifunctional Proline Utilization A From Sinorhizobium Meliloti, Emma Bitterman

Honors Program: Senior Projects (Public)

The reduction potential of flavin bound to Sinorhizobium meliloti proline utilization A (SmPutA) is beneficial in providing vital information on enzyme activity and the active site environment. Flavin is crucial in biological metabolism such as aerobic respiration and other important processes like oxygen activation that are catalyzed by flavin-dependent enzymes. (4). In this study, we seek to determine whether the redox potential of SmPutA-bound flavin can be used to characterize potential long-distance communication and analyze the possibilities of inactivation reversibility. SmPutA is a large bifunctional enzyme that catalyzes the overall oxidation of proline to glutamate via two catalytic domains (1). …

Screening For Penicillin G Acylase (Pga)-Producing Bacteria And Gene Cloning Using Degenerate Oligonucleotide Primed-Pcr, Masdalifah Masdalifah, Sri Rezeki Wulandari, Gabriela Christy Sabbathini, Maria Ulfah, Dini Achnafani, Ahmad Wibisana, Feronika Heppy Sriherfyna, Is Helianti, Niknik Nurhayati

Makara Journal of Science

The growing concern over antibiotic resistance has driven global efforts to explore innovative solutions, including the use of Penicillin G acylase (PGA) to produce semisynthetic β-lactam antibiotics. This study screened four potential in-tracellular PGA-producing bacteria: Alcaligenes faecalis InaCC B444 (AfPGA), Kluyvera cryocrescens InaCC B850 (KcPGA), Providencia rettgeri InaCC B25 (Pr25PGA), and P. rettgeri InaCC B466 (Pr466PGA). Penicillin G Acylase encoding genes (pgas) were isolated from them using a Degenerate Oligonucleotide Primed-PCR (DOP-PCR) approach and sequenced. Microbiological assays confirmed all tested crude extracts to exhibit inhibitory effects. Penicillin G was used for evaluating hydrolytic activity and 6-Amino Penicillanic Acid (6-APA) coupled …

Applications Of Archaeal Antioxidant Coenzyme M As An Agricultural Biostimulant, Jeremy Hunter Brown

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

As the demand to meet global food security goals continue to increase, the need to increase efficiency and productivity of agricultural output also rises. This calls for innovative and cost-effective methods for improving plant growth and yield. Here we explore how antioxidants, molecules that inhibit oxidation and are necessary for redox based signaling and redox homeostasis, can be utilized as chemical biostimulants. Specifically, we investigated Coenzyme M, an antioxidant from archaea that holds potential economic advantages over other antioxidants. Chapter 1 provides a comprehensive review of antioxidants and how exogenously application of them affects plant growth and biology, highlighting the …

The C-Terminal Phdvc5hch Tandem Domain Of Nsd2 Is A Combinatorial Reader Of Modified H3k4 And Tri-Methylated H3k27 That Regulates Transcription Of Cell Adhesion Genes In Multiple Myeloma, Andrea Berardi, Charlotte Leonie Kaestner, Michela Ghitti, Giacomo Quilici, Paolo Cocomazzi, Jianping Li, Federico Ballabio, Chiara Zucchelli, Stefan Knapp, Jonathan Licht, Giovanna Musco

Department of Pharmacology, Physiology, and Cancer Biology Faculty Papers

Histone methyltransferase NSD2 (MMSET) overexpression in multiple myeloma (MM) patients plays an important role in the development of this disease subtype. Through the expansion of transcriptional activating H3K36me2 and the suppression of repressive H3K27me3 marks, NSD2 activates an aberrant set of genes that contribute to myeloma growth, adhesive and invasive activities. NSD2 transcriptional activity also depends on its non-catalytic domains, which facilitate its recruitment to chromatin through histone binding. In this study, using NMR, ITC and molecular dynamics simulations, we show that the tandem PHD domain of NSD2 (PHDVC5HCHNSD2) is a combinatorial reader of unmodified histone H3K4 and tri-methylated H3K27 …

Identifying Notch-Regulated Genes Using A Specific Notch Signaling Inhibitor, Hammed Gafar

EWU Masters Thesis Collection

Bone remodeling is a dynamic process that requires a balance between bone resorption by osteoclasts and bone formation by osteoblasts to maintain skeletal integrity. Disruptions to this equilibrium can lead to pathological conditions such as osteoporosis. Osteoclasts originate from macrophages, and their differentiation is regulated by several signaling pathways, notably the notch signaling pathway. Gamma-secretase, an enzyme crucial for initiating notch signaling, can be inhibited by DAPT. However, DAPT also targets non-Notch substrates, complicating the identification of genes specifically regulated by Notch. To address this limitation, this study employed IMR-1A, a selective Notch pathway inhibitor that disrupts the assembly of …

Reversible Degradation Of Peptidoglycan By Lytic Transglycosylases, Aaron Devereaux

Theses and Dissertations (Comprehensive)

Antimicrobial resistance continues to be a burden on the global healthcare system with an estimated cost of billions of dollars and millions of deaths each year. Recently, there has been little to no development on new antibiotics to treat bacterial infection, and any that are developed become resisted to within a few years. Both Gram-positive and Gram-negative bacteria contain a mesh-like layer called peptidoglycan (PG) that surrounds their cells providing strength, cell shape, and protection from their environments. This layer is a polymer of N-acetylmuramic acid (MurNAc) and N-acetylglucosamine (GlcNAc) connected via a b-1,4-glycosidic bond, with each strand being cross-linked …

Redox Control In A Fused Electron Transfer Flavoprotein From A Thermophilic Archaeon And Expanded Significance Of A Hydrogen Bond From A Conserved Histidine Residue That Contributes To Flavin Redox Tuning And Activation For Covalent Modification, Debarati Das

Theses and Dissertations--Chemistry

In absence of O₂ as terminal electron acceptors in anaerobic bacteria and archaea, carbohydrate metabolism is 15 times less efficient compared to aerobic energy metabolism resulting in energy deficit conditions. Despite their meager resources these anaerobes were able to generate H₂ and a chemiosmotic potential able to drive energy demanding reactions such as CO₂ or N₂ fixation. These observations raised concerns as production of high energy reductants (H₂) from mediocre fuels (NADH) defied the laws of thermodynamics.

In 2008, a known mechanism “electron bifurcation” but with flavins as redox mediators instead of quinones was …

Determination Of The Kinetic Parameters Of Cholesterol Oxidation Using Cholesterol Oxidase From Streptomyces Sp., Meka Saima Perdani, Heri Hermansyah, Muhamad Sahlan, Dwini Normayulisa Putri, Teguh Pambudi, Anggi Khairina Hanum Hasibuan

Makara Journal of Technology

Cholesterol oxidase (CO) was successfully produced from Streptomyces sp. via the submerged fermentation method, and 69 U/mL enzyme activity was obtained. This study aimed to determine cholesterol oxidation kinetics and the production of CO as a catalyst. The enzyme was diluted to 0.15, 0.075, and 0.00375 U/mL for the oxidation reaction. The substrate was also prepared in three concentrations: 3.23, 6.46, and 12.93 mM. The optimization of conditions for enzymatic cholesterol oxidation was investigated through measurement of the effect of initial cholesterol and enzyme concentrations. Cholesterol concentration was rapidly measured via high-performance liquid chromatography (HPLC). The kinetics of CO were …

Opa1 And Disease-Causing Mutants Perturb Mitochondrial Nucleoid Distribution, J. Macuada, I. Molina-Riquelme, G. Vidal, N. Pérez-Bravo, C. Vásquez-Trincado, G. Aedo, D. Lagos, P. Yu-Wai-Man, R. Horvath, T. J. Rudge, B. Cartes-Saavedra, V. Eisner

Department of Pathology, Anatomy, and Cell Biology Faculty Papers

Optic atrophy protein 1 (OPA1) mediates inner mitochondrial membrane (IMM) fusion and cristae organization. Mutations in OPA1 cause autosomal dominant optic atrophy (ADOA), a leading cause of blindness. Cells from ADOA patients show impaired mitochondrial fusion, cristae structure, bioenergetic function, and mitochondrial DNA (mtDNA) integrity. The mtDNA encodes electron transport chain subunits and is packaged into nucleoids spread within the mitochondrial population. Nucleoids interact with the IMM, and their distribution is tightly linked to mitochondrial fusion and cristae shaping. Yet, little is known about the physio-pathological relevance of nucleoid distribution. We studied the effect of OPA1 and ADOA-associated mutants on …

Post-Transcriptional Methylation Of Mitochondrial-Trna Differentially Contributes To Mitochondrial Pathology, Sunita Maharjan, Howard Gamper, Yuka Yamaki, Thomas W. Christian, Robert Y. Henley, Nan-Sheng Li, Takeo Suzuki, Tsutomu Suzuki, Joseph A. Piccirilli, Meni Wanunu, Erin L. Seifert, Douglas C. Wallace, Ya-Ming Hou

Department of Biochemistry and Molecular Biology Faculty Papers

Human mitochondrial tRNAs (mt-tRNAs), critical for mitochondrial biogenesis, are frequently associated with pathogenic mutations. These mt-tRNAs have unusual sequence motifs and require post-transcriptional modifications to stabilize their fragile structures. However, whether a modification that stabilizes a wild-type (WT) mt-tRNA would also stabilize its pathogenic variants is unknown. Here we show that the N¹-methylation of guanosine at position 9 (m¹G9) of mt-Leu(UAA), while stabilizing the WT tRNA, has a destabilizing effect on variants associated with MELAS (mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes). This differential effect is further demonstrated, as removal of the m¹G9 …

Aars Online: A Collaborative Database On The Structure, Function, And Evolution Of The Aminoacyl-Trna Synthetases, Jordan Douglas, Haissi Cui, John J. Perona, Oscar Vargas-Rodriguez, Henna Tyynismaa, Claudia Alvarez Carreño, Jiqiang Ling, Lluís Ribas De Pouplana, Xiang-Lei Yang, Michael Ibba, Hubert Becker, Frédéric Fischer, Marie Sissler, Charles W. Carter Jr., Peter Wills

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

The aminoacyl-tRNA synthetases (aaRS) are a large group of enzymes that implement the genetic code in all known biological systems. They attach amino acids to their cognate tRNAs, moonlight in various translational and non-translational activities beyond aminoacylation, and are linked to many genetic disorders. The aaRS have a subtle ontology characterized by structural and functional idiosyncrasies that vary from organism to organism, and protein to protein. Across the tree of life, the 22 coded amino acids are handled by 16 evolutionary families of Class I aaRS and 21 families of Class II aaRS. We introduce AARS Online, an interactive Wikipedia-like …

A Homogeneous Time-Resolved Fluorescence Screen To Identify Sirt2 Deacetylase And Defatty-Acylase Inhibitors, Jie Yang, Joel Cassel, Brian C Boyle, Daniel Oppong, Young-Hoon Ahn, Brian P Weiser

Rowan-Virtua School of Osteopathic Medicine Departmental Research

Human sirtuin-2 (SIRT2) has emerged as an attractive drug target for a variety of diseases. The enzyme is a deacylase that can remove chemically different acyl modifications from protein lysine residues. Here, we developed a high-throughput screen based on a homogeneous time-resolved fluorescence (HTRF) binding assay to identify inhibitors of SIRT2's demyristoylase activity, which is uncommon among many ligands that only affect its deacetylase activity. From a test screen of 9600 compounds, we identified a small molecule that inhibited SIRT2's deacetylase activity (IC50 = 7 μM) as well as its demyristoylase activity (IC50 = 37 μM). The inhibitor was composed …

The Purification And Thermal Stability Of The Peroxidase Enzyme In Cucurbita Moschata, Garen Hamner

Senior Honors Theses

Peroxidases are enzymes that catalyze the reduction of hydrogen peroxide to water while oxidizing organic substrates and are valuable in spheres like industrial and medical applications and histochemistry. Limitations still exist in the use of the well-studied horseradish peroxidase for certain activities due to limitations like poor thermal stability, thus the search for novel peroxidases that can overcome these limitations is an active area of research. Butternut squash peroxidase (Cucurbita moschata) (BSP) shows promise due to significant activity being found in the skin and apparent enhanced thermal stability, but an efficient purification scheme for it is lacking, as well as …

Managing Stress: A Study Of Stress Response Mechanisms In Mycobacteria, Augusto C. Hunt Serracin

Biology Dissertations - Archive

Mycobacteria encompass many pathogenic species known to cause severe disease in humans. A well-known example is Mycobacterium tuberculosis (Mtb), the causative agent of the lung disease tuberculosis, which kills millions of humans worldwide yearly. Pathogenic mycobacteria like Mtb are challenging to treat because of their innate ability to adapt to environmental stress. Their unique cell physiology and conserved stress responses allow them to combat biological insults, regulate growth, and regulate genes involved in stress; all these responses increase tolerance to antibiotics. The current therapies to treat mycobacterial infections are lengthy and, at times, unsuccessful, partly due to antibiotic tolerance. A …

Variables Affecting The Extraction Of Antioxidants In Cold And Hot Brew Coffee: A Review, Brian Yust, Frank Wilkinson, Niny Rao

College of Life Sciences Faculty Papers

Coffee beans are a readily available, abundant source of antioxidants used worldwide. With the increasing interest in and consumption of coffee beverages globally, research into the production, preparation, and chemical profile of coffee has also increased in recent years. A wide range of variables such as roasting temperature, coffee grind size, brewing temperature, and brewing duration can have a significant impact on the extractable antioxidant content of coffee products. While there is no single standard method for measuring all of the antioxidants found in coffee, multiple methods which introduce the coffee product to a target molecule or reagent can be …

Mutational Analysis Of The Nitrogenase Carbon Monoxide Protective Protein Cown Reveals That A Conserved C‑Terminal Glutamic Acid Residue Is Necessary For Its Activity, Dustin L. Willard, Joshuah J. Arellano, Mitch Underdahl, Terrence M. Lee, Avinash S. Ramaswamy, Gabriella Fumes, Agatha Kliman, Emily Y. Wong, Cedric P. Owens

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Nitrogenase is the only enzyme that catalyzes the reduction of nitrogen gas into ammonia. Nitrogenase is tightly inhibited by the environmental gas carbon monoxide (CO). Many nitrogen fixing bacteria protect nitrogenase from CO inhibition using the protective protein CowN. This work demonstrates that a conserved glutamic acid residue near the C-terminus of Gluconacetobacter diazotrophicus CowN is necessary for its function. Mutation of the glutamic acid residue abolishes both CowN’s protection against CO inhibition and the ability of CowN to bind to nitrogenase. In contrast, a conserved C-terminal cysteine residue is not important for CO protection by CowN. Overall, this work …