Enzymes and Coenzymes Commons^™

Investigating Propargyl-Linked Antifolates In Inhibiting Bacterial And Fungal Dihydrofolate Reductase, Joshua Andrade

Honors Scholar Theses

Antimicrobial agents have been invaluable in reducing illness and death associated with bacterial infection. However, over time, bacteria have evolved resistance to all major drug classes as a result of selective pressure. The advancement of new drug compounds is therefore vital. The Anderson-Wright Lab has focused on developing potent and selective inhibitors of dihydrofolate reductase (DHFR), an enzyme key in cell proliferation and survival, in several pathogenic species. The lab has found that a set of compounds, known as propargyl-linked antifolates, are DHFR inhibitors that are both biologically effective and have strong pharmacokinetic properties.

The efficacy of novel propargyl-linked antifolates …

Purple Urine Bag Syndrome: Regulation Of Pyrimidine Enzymes, Ashley N. Broadway

Honors Theses

Purple Urine Bag Syndrome, PUBS, is a unique condition that shows an interesting discoloration of the urine from women who have a chronic catheter. This study focused on the regulation of enzyme activities to determine the effects that may create an environment where PUBS is seen in patients with catheters. In this study, the reductive pyrimidine pathway was used to read out the bacteria Pseudomonas aeruginosa ATCC 15692. This microorganism expresses a pathway that synthesizes indoxyl from tryptophan. The bacteria strains were grown using various carbon and nitrogen sources. Concentrations of acetonitrile at 2 mM and 10 mM, concentrations of …

Metal Stopping Reagents Facilitate Discontinuous Activity Assays Of The De Novo Purine Biosynthesis Enzyme Pure, Kelly L. Sullivan, Loredana C. Huma, Elwood Mullins, Michael E. Johnson, T. Joseph Kappock

Department of Biochemistry Faculty Publications

The conversion of 5-aminoimidazole ribonucleotide (AIR) to 4-carboxy-AIR (CAIR) represents an unusual divergence in purine biosynthesis: microbes and nonmetazoan eukaryotes use class I PurEs while animals use class II PurEs. Class I PurEs are therefore a potential antimicrobial target; however, no enzyme activity assay is suitable for high throughput screening (HTS). Here we report a simple chemical quench that fixes the PurE substrate/product ratio for 24 h, as assessed by the Bratton-Marshall assay (BMA) for diazotizable amines. The ZnSO₄ stopping reagent is proposed to chelate CAIR, enabling delayed analysis of this acid-labile product by BMA or other HTS methods

Mechanism Underlying Ikk Activation Mediated By The Linear Ubiquitin Chain Assembly Complex (Lubac), Hiroaki Fujita, Simin Rahighi, Mariko Akita, Ryuichi Kato, Yoshiteru Sasaki, Soichi Wakatsuki, Kazuhiro Iwai

Pharmacy Faculty Articles and Research

The linear ubiquitin chain assembly complex (LUBAC) ligase, consisting of HOIL-1L, HOIP, and SHARPIN, specifically generates linear polyubiquitin chains. LUBAC-mediated linear polyubiquitination has been implicated in NF-κB activation. NEMO, a component of the IκB kinase (IKK) complex, is a substrate of LUBAC, but the precise molecular mechanism underlying linear chain-mediated NF-κB activation has not been fully elucidated. Here, we demonstrate that linearly polyubiquitinated NEMO activates IKK more potently than unanchored linear chains. In mutational analyses based on the crystal structure of the complex between the HOIP NZF1 and NEMO CC2-LZ domains, which are involved in the HOIP-NEMO interaction, NEMO mutations …

Synthesis And Evaluation Of C-Src Kinase Inhibitory Activity Of Pyridin-2(1h)-One Derivatives, Karam Chand, Suchita Prasad, Rakesh Tiwari, Amir Nasrolahi Shirazi, Sumit Kumar, Keykavous Parang, Sunil K. Sharma

Pharmacy Faculty Articles and Research

Src kinase, a prototype member of the Src family of kinases (SFKs), is over-expressed in various human tumors, and has become a target for anticancer drug design. In this perspective, a series of eighteen 2-pyridone derivatives were synthesized and evaluated for their c-Src kinase inhibitory activity. Among them, eight compounds exhibited c-Src kinase inhibitory activity with IC50 value of less than 25 mu M. Compound 1-[2-(dimethylamino)ethyl]-5-(2-hydroxy-4-methoxybenzoyl)pyridin-2(1H)-one (36) exhibited the highest c-Src kinase inhibition with an IC50 value of 12.5 mu M. Furthermore, the kinase inhibitory activity of compound 36 was studied against EGFR, MAPK and PDK, however no significant activity …

Structure-Functional Prediction And Analysis Of Cancer Mutation Effects In Protein Kinases, Anshuman Dixit, Gennady M. Verkhivker

Mathematics, Physics, and Computer Science Faculty Articles and Research

A central goal of cancer research is to discover and characterize the functional effects of mutated genes that contribute to tumorigenesis. In this study, we provide a detailed structural classification and analysis of functional dynamics for members of protein kinase families that are known to harbor cancer mutations. We also present a systematic computational analysis that combines sequence and structure-based prediction models to characterize the effect of cancer mutations in protein kinases. We focus on the differential effects of activating point mutations that increase protein kinase activity and kinase-inactivating mutations that decrease activity. Mapping of cancer mutations onto the conformational …

Investigating Structure And Protein-Protein Interactions Of Key Post-Type Ii Pks Tailoring Enzymes, Theresa E. Downey

Theses and Dissertations--Pharmacy

Type II polyketide synthase (PKS) produced natural products have proven to be an excellent source of pharmacologically relevant molecules due to their rich biological activities and chemical scaffolds. Type II-PKS manufactured polyketides share similar polycyclic aromatic backbones leaving their diversity to stem from various chemical additions and alterations facilitated by post-PKS tailoring enzymes. Evidence suggests that post-PKS tailoring enzymes form complexes in order to facilitate the highly orchestrated process of biosynthesis. Thus, protein-protein interactions between these enzymes must play crucial roles in their structures and functions. Despite the importance of these interactions little has been done to study them. In …

The Effect Of Maté On Enzymes Involved In The Recovery From Oxidative Stress, Amina Sadik, Theodore Chang

College of Osteopathic Medicine (TUN) Publications and Research

In comparing the effect of Maté to that of green tea, it has been shown that Maté has higher anti-oxidative properties. We have shown that the extract of Yerba Maté, paraguariensis, leaves does indeed have strong anti-oxidative properties through the evaluation of its scavenging activity and its ability of assist cardiomyocytes in their recovery from induced oxidative stress using both spectroscopy, a colorimetric assay and flow cytometry. In order to elucidate the mechanism behind this action, we quantified the enzymes known to be expressed naturally by cells under oxidative stress such as glutathione peroxidase, superoxide dismutase, and catalase. These enzymes …

Biochemical Assay Optimization And Computational Screening Efforts To Identify Potential Luxs Inhibitors, Keeshia Q. Wang

Master's Theses

Quorum sensing (QS) is a process of coordination of bacterial gene expression in response to cell population. System two QS is regulated by the small signaling molecule autoinducer-2 (AI-2) and is implicated in the infectious behaviors of various bacterial species. AI-2 is biosynthesized from S-ribosylhomocysteine (SRH) by the enzyme LuxS and induces interspecies cell-to-cell communication. Inhibition of LuxS would therefore inhibit interspecies QS. Herein, a search for novel molecular species that will competitively bind with SRH in the LuxS binding site is performed in silico. Computational screening results are then validated in vitro using an optimized LuxS inhibition …

Radiosensitization Of Head & Neck Carcinoma Cells By Linifanib, A Receptor Tyrosine Kinase Inhibitor, Heng-Wei Hsu

Loma Linda University Electronic Theses, Dissertations & Projects

Tumor angiogenesis is a hallmark of advanced cancers and promotes invasion and metastasis. Over 90% of head and neck squamous cell carcinomas (HNSCC) express angiogenic factors such as vascular endothelial growth factor (VEGF). Since radiotherapy is one of the most commonly used treatments for HNSCC, it is imperative to identify the interactions between antiangiogenic therapy and radiotherapy, and to develop combination therapy to improve clinical outcome. The mechanisms between antiangiogenic agents and ionizing radiation are complicated and involve many interactions between the vasculature, tumor stroma and tumor cells. The proliferation and metastasis of tumor cells rely on angiogenesis/blood vessel formation. …

Investigation Of Commercial Milk Enzyme-Linked Immunosorbent Assay (Elisa) Kits: Specificity And Utility For Residues Of Foods Subjected To Proteolysis During Processing, Katherine O. Ivens

Department of Food Science and Technology: Dissertations, Theses, and Student Research

Analytical methods, such as enzyme-linked immunosorbent assays (ELISA), are used to detect and quantify residues from allergenic sources in food products. However, ELISAs have not been validated for use in foods that have been exposed to proteolysis. This thesis explores the specificities, sensitivities, and capabilities of commercially-available milk ELISA kits for detecting milk residues in cheeses that have undergone varying degrees of proteolysis.

The specificity, accuracy, and consistency of twelve commercially-available milk ELISA kits for individual milk proteins and commonly used milk-derived ingredients, including α-,β-, and κ-casein, β-lactoglobulin, α-lactalbumin, non-fat dry milk, sodium caseinate, and whey protein concentrate were evaluated. …

Enzymatic Hydrolysis Of Biomass At High-Solids Loadings – A Review, Alicia A. Modenbach, Sue E. Nokes

Biosystems and Agricultural Engineering Faculty Publications

Enzymatic hydrolysis is the unit operation in the lignocellulose conversion process that utilizes enzymes to depolymerize lignocellulosic biomass. The saccharide components released are the feedstock for fermentation. When performed at high-solids loadings (≥ 15% solids, w/w), enzymatic hydrolysis potentially offers many advantages over conversions performed at low- or moderate-solids loadings, including increased sugar and ethanol concentrations and decreased capital and operating costs.

The goal of this review is to provide a consolidated source of information on studies using high-solids loadings in enzymatic hydrolysis. Included in this review is a brief discussion of the limitations, such as a lack of available …

Rescuing Acetylcholinesterase From Nerve Agent Inhibition: Protein Dynamics Driven Drug Discovery, Aiyana M. Emigh, Brian Bennion

STAR Program Research Presentations

Severe morbidity and mortality consequences result from irreversible inhibition of human acetylcholinesterase by organophosphates (OPs). Oxime-based reactivators are currently the only available treatments but lack efficacy in the central nervous system (CNS) where the most damage occurs. Computational docking and molecular dynamics (MD) simulations reveal complex structural barriers that may reduce oxime efficacy. These results may guide future drug designs of more effective countermeasures.

Synthesis Of Pyrazolo[3,4-D]Pyrimidine Derivatives And Evaluation Of Their Src Kinase Inhibitory Activities, Anil Kumar, Guofeng Ye, Xianfeng Gu, Yuehao Wang, Gongqin Sun, Keykavous Parang

Pharmacy Faculty Articles and Research

A series of pyrazolo[3,4-d]pyrimidine derivatives was synthesized and evaluated for the Src kinase inhibitory activities. Compound 6e and 10c exhibited inhibition of Src kinase with an IC50 value of 5.6 and 5.1 μM, respectively. Hydroxamate derivative 15a was found to be a metal-mediated inhibitor for human Csk with an IC50 value of 2.0 μM showing 56-fold selectivity over Src kinase inhibition.

Biosynthetic Pathway Of The Aminoribosyl Component Of Lipopeptidyl Nucleoside Antibiotics, Xiuling Chi

Theses and Dissertations--Pharmacy

Several lipopeptidyl nucleoside antibiotics that inhibit bacterial translocase I (MraY) involved in peptidoglycan cell wall biosynthesis contain an aminoribosyl moiety, an unusual sugar appendage in natural products. A-90289 and muraminomicin are the two representative antibiotics that belong to this family. Bioinformatic analysis of the biosynthetic A-90289 gene clusters revealed that five enzymes are likely involved in the assembly and attachment of the aminoribosyl unit. These enzymes of A-90289 are functionally assigned by in vitro characterization. The results reveal a unique ribosylation pathway that highlighted by uridine-5′-monophosphate as the source of the sugar, a phosphorylase strategy to generate a sugar-1-phosphate, and …

Key Players In Reverse Cholesterol Transport: The Plasma Enzyme Lcat, Christopher J. Pechura

Undergraduate Research Posters 2012

Lecithin cholesterol acyltransferase (LCAT) is a plasma enzyme that remodels nascent high density lipoprotein (HDL) into a mature form called spherical HDL. The model will be used in the future to map the amino acid residues from LCAT and the protein component of nascent HDL (apoA1) involved in mutual interaction, and to identify LCAT residues interacting with the lipid phase of nascent HDL.

Expression And Distribution Of Thiol-Regulating Enzyme, Glutaredoxin 2 In Porcine Ocular Tissues, Bijaya Prasad Upadhyaya

School of Veterinary and Biomedical Sciences: Dissertations, Theses, and Student Research

Glutaredoxin 2 (Grx2), a thiol-regulating enzyme of oxidoreductase family and a mitochondrial isozyme of glutaredoxin 1, was discovered 11 years ago in our laboratory. Grx2 is present in the lens where it shows dethiolase, peroxidase, and ascorbate recycling activities. Recently, Grx2 has also been identified to protect the mitochondrial electron transport system with anti-apoptotic function. Since other eye tissues besides the lens are rich in mitochondria and are very sensitive to oxidative stress, we speculate the presence of Grx2 therein as an important redox regulator. This study is to investigate the expression and distribution of Grx2 in ocular tissues using …

Selectivity Of The Ubiquitin-Binding Modules, Simin Rahighi, Ivan Dikic

Pharmacy Faculty Articles and Research

Ubiquitin-binding modules are constituents of cellular proteins that mediate the effects of ubiquitylation by making transient, non-covalent interactions with ubiquitin molecules. While some ubiquitin- binding modules bind single ubiquitin moieties, others are selective for specific ubiquitin chains of different linkage types and lengths. In recent years, functions of ubiquitin chains that are polymerized through their Lys or N-terminal Met (i.e. linear chains) residues have been linked to a variety of cellular processes. Selectivity of ubiquitin-binding modules for different ubiquitin chain types appears as a key to the distinct regulatory consequences during protein quality control pathways, receptor endocytosis, gene transcription, signaling …

The Molecular Basis Of Fitness And Transmissibility Of Neuraminidase Inhibitor Resistant Influenza A Viruses, Susu Duan

Theses and Dissertations (ETD)

Neuraminidase (NA) inhibitors including oral oseltamivir and inhaled zanamivir are among the first line of defense against influenza virus infection. Development of resistance to NA inhibitors is a huge drawback for limited options for the control of influenza. During the first decade of NA inhibitor use, the detection rates of resistance to both NA inhibitors had remained low in circulating influenza viruses. However, the 2008~2009 season was marked by a radical increase of prevalence of oseltamvir resistance from <1% to >90% in worldwide surveillance in less than a year. The resistance was solely linked to NA H275Y variants of seasonal H1N1 viruses, …

Enantioselective Demethylation: The Key To The Nornicotine Enantiomeric Composition In Tobacco Leaf, Bin Cai

Theses and Dissertations--Plant and Soil Sciences

Nicotine and nornicotine are the two main alkaloids that accumulate in Nicotiana tabacum L. (tobacco), and nornicotine is the N-demethylation metabolite of nicotine. Nicotine is synthesized in the root, and probably primarily in the root tip. Both nicotine and nornicotine exist as two isomers that differ from each other by the orientation of H atom at the C-2' position on the pyrrolidine ring. (S)-nicotine is the dominant form in tobacco leaf and the enantiomer fraction of nicotine (EF_nic), the fraction of (R)-enantiomer over the total nicotine, is approximately 0.002. Despite considerable efforts to elucidate nicotine and nornicotine …