Medicine and Health Sciences Commons^™

Kinetics Of Dextromethorphan-O-Demethylase Activity And Distribution Of Cyp2d In Four Commonly-Used Subcellular Fractions Of Rat Brain, Barent N. Dubois, Farideh Amirrad, Reza Mehvar

Pharmacy Faculty Articles and Research

The purpose of this study was to compare the enzymatic kinetics and distribution of cytochrome P450 2D (CYP2D) among different rat brain subcellular fractions.

Rat brains were used to prepare total membrane, crude mitochondrial, purified mitochondrial, and microsomal fractions, in addition to total homogenate. Michaelis–Menten kinetics of the brain CYP2D activity was estimated based on the conversion of dextromethorphan (DXM) to dextrorphan using UPLC-MS/MS. Protein levels of CYP2D and subcellular markers were determined by Western blot.

Microsomal CYP2D exhibited high affinity and low capacity, compared with the mitochondrial CYP2D that had a much lower (∼50-fold) affinity but a higher (∼six-fold) …

Nrh:Quinone Oxidoreductase 2 (Nqo2) And Glutaminase (Gls) Both Play A Role In Large Extracellular Vesicles (Lev) Formation In Preclinical Lncap-C4-2b Prostate Cancer Model Of Progressive Metastasis, Thambi Dorai, Ankeeta Shah, Faith Summers, Rajamma Mathew, Jing Huang, Tze-Chen Hsieh, Joseph M. Wu

NYMC Faculty Publications

In the course of studies aimed at the role of oxidative stress in the development of metastatic potential in the LNCaP-C4-2B prostate cancer progression model system, we found a relative decrease in the level of expression of the cytoplasmic nicotinamide riboside: quinone oxidoreductase (NQO2) and an increase in the oxidative stress in C4-2B cells compared to that in LNCaP or its derivatives C4 and C4-2. It was also found that C4-2B cells specifically shed large extracellular vesicles (LEVs) suggesting that these LEVs and their cargo could participate in the establishment of the osseous metastases. The level of expression of caveolin-1 …

Correcting Glucose-6-Phosphate Dehydrogenase Deficiency With A Small-Molecule Activator, Sunhee Hwang, Karen Mruk, Simin Rahighi, Andrew G. Raub, Che-Hong Chen, Lisa E. Dorn, Naoki Horikoshi, Soichi Wakatsuki, James K. Chen, Daria Mochly-Rosen

Pharmacy Faculty Articles and Research

Glucose-6-phosphate dehydrogenase (G6PD) deficiency, one of the most common human genetic enzymopathies, is caused by over 160 different point mutations and contributes to the severity of many acute and chronic diseases associated with oxidative stress, including hemolytic anemia and bilirubin-induced neurological damage particularly in newborns. As no medications are available to treat G6PD deficiency, here we seek to identify a small molecule that corrects it. Crystallographic study and mutagenesis analysis identify the structural and functional defect of one common mutant (Canton, R459L). Using high-throughput screening, we subsequently identify AG1, a small molecule that increases the activity of the wild-type, the …

Ubiquitin Regulation: The Histone Modifying Enzyme's Story, Jianlin Wang, Zhaoping Qiu, Yadi Wu

Pharmacology and Nutritional Sciences Faculty Publications

Histone post-translational modifications influence many fundamental cellular events by regulating chromatin structure and gene transcriptional activity. These modifications are highly dynamic and tightly controlled, with many enzymes devoted to the addition and removal of these modifications. Interestingly, these modifying enzymes are themselves fine-tuned and precisely regulated at the level of protein turnover by ubiquitin-proteasomal processing. Here, we focus on recent progress centered on the mechanisms regulating ubiquitination of histone modifying enzymes, including ubiquitin proteasomal degradation and the reverse process of deubiquitination. We will also discuss the potential pathophysiological significance of these processes.

Direct Quantification Of Deubiquitinating Enzyme Activity In Single Intact Cells, Nora Safabakhsh

LSU Doctoral Dissertations

Challenges in drug efficacy occur during the treatment of most types of cancer due to the heterogeneity of the tumor microenvironment. This has led to the development of personalized medicine. Due to the clinical success of the proteasome inhibitors Bortezomib and Carfilzomib in treatment of multiple myeloma, interest has shifted towards molecularly-targeted chemotherapeutics for ubiquitin-proteasome system (UPS). Deubiquitinating enzymes (DUBs) are an essential part of this pathway which have been found to promote Bortezomib resistance in multiple myeloma patients. Unfortunately, there is a lack of specific, high throughput biochemical assays to characterize DUB activity in patient samples before and after …

Molecular Determinants Of Substrate Specificity In Human Insulin-Degrading Enzyme, Lazaros Stefanidis, Nicholas D. Fusco, Samantha E. Cooper, Jilian E. Smith-Carpenter, Benjamin J. Alper

Chemistry & Physics Faculty Publications

Insulin-degrading enzyme (IDE) is a 110 kDa chambered zinc metalloendopeptidase that degrades insulin, amyloid beta, and other intermediate-sized aggregation prone peptides that adopt β-structures. Structural studies of IDE in complex with multiple physiological substrates have suggested a role for hydrophobic and aromatic residues of the IDE active site in substrate binding and catalysis. Here, we examine functional requirements for conserved hydrophobic and aromatic IDE active site residues that are positioned within 4.5 Angstroms of IDE bound insulin B chain and amyloid beta peptides in the reported crystal structures for the respective enzyme-substrate complexes. Charge, size, hydrophobicity, aromaticity, and other functional …

The N-Terminal Methyltransferase Homologs Nrmt1 And Nrmt2 Exhibit Novel Regulation Of Activity Through Heterotrimer Formation., Jon David Faughn

Electronic Theses and Dissertations

Protein, DNA, and RNA methyltransferases have an ever-expanding list of novel substrates and catalytic activities. Even within families and between homologs, it is becoming clear the intricacies of methyltransferase specificity and regulation are far more diverse than originally thought. In addition to specific substrates and distinct methylation levels, methyltransferase activity can be altered through formation of complexes with close homologs. This work involves the N-terminal methyltransferase homologs NRMT1 and NRMT2. NRMT1 is a ubiquitously expressed distributive trimethylase. NRMT2 is a monomethylase expressed at low levels and in a tissue-specific manner. They are both nuclear methyltransferases with overlapping target consensus sequences …

“Do We Know Jack” About Jak? A Closer Look At Jak/Stat Signaling Pathway, Emira Bousoik, Hamidreza Montazeri Aliabadi

Pharmacy Faculty Articles and Research

Janus tyrosine kinase (JAK) family of proteins have been identified as crucial proteins in signal transduction initiated by a wide range of membrane receptors. Among the proteins in this family JAK2 has been associated with important downstream proteins, including signal transducers and activators of transcription (STATs), which in turn regulate the expression of a variety of proteins involved in induction or prevention of apoptosis. Therefore, the JAK/STAT signaling axis plays a major role in the proliferation and survival of different cancer cells, and may even be involved in resistance mechanisms against molecularly targeted drugs. Despite extensive research focused on the …

Anti-Tumor Activity Of Phenoxybenzamine And Its Inhibition Of Histone Deacetylases, Mario A. Inchiosa

NYMC Faculty Publications

The principal finding from this study was the recognition that the α-adrenergic antagonist, phenoxybenzamine, possesses histone deacetylase inhibitory activity. Phenoxybenzamine is approved by the United States Food and Drug Administration for the treatment of hypertensive crises associated with tumors of the adrenal medulla, pheochromocytomas. It has several "off label" indications relative to its capacity to relax vascular smooth muscle and smooth muscle of the urogenital tract. The drug also has a long history of apparent efficacy in ameliorating, and perhaps reversing, the severe symptoms of neuropathic pain syndromes. Our interest in this feature of the drug relates to the fact …

Site-Selective Modification Of Peptides And Proteins Via Organocatalyzed Henry Reaction, Zilma Pereira Muneeswaran

Seton Hall University Dissertations and Theses (ETDs)

In this research, peptides and protein containing serine on the N-terminus underwent site-selective modification following organocatalyzed bioconjugation that offered an additional functional group. It was shown that transforming the N-terminus serine to an aldehyde allowed site-specific bioconjugation to occur by utilizing the well-known Henry reaction. This method also grants a safer pathway for bioconjugation utilizing “green-chemistry” and biocompatible conditions. Amino acids and amino acid derived organocatalysts were utilized in the Henry reaction resulting in yields of up to 86 % conversion. Promising preliminary results were achieved in this research using peptides and myoglobin as the bioconjugation targets. Further investigation to …

Dissecting Structure-Encoded Determinants Of Allosteric Cross-Talk Between Post-Translational Modification Sites In The Hsp90 Chaperones, Gabrielle Stetz, Amanda Tse, Gennady M. Verkhivker

Mathematics, Physics, and Computer Science Faculty Articles and Research

Post-translational modifications (PTMs) represent an important regulatory instrument that modulates structure, dynamics and function of proteins. The large number of PTM sites in the Hsp90 proteins that are scattered throughout different domains indicated that synchronization of multiple PTMs through a combinatorial code can be invoked as an important mechanism to orchestrate diverse chaperone functions and recognize multiple client proteins. In this study, we have combined structural and coevolutionary analysis with molecular simulations and perturbation response scanning analysis of the Hsp90 structures to characterize functional role of PTM sites in allosteric regulation. The results reveal a small group of conserved PTMs …

Effects Of Mitochondrial Nadp+-Dependent Isocitrate Dehydrogenase Deficiency On Fructose-Induced Obesity In Mice, Allison Michelle Montalbano, Kaleigh Elizabeth Beane

Human Nutrition and Hospitality Management Undergraduate Honors Theses

Obesity prevalence in the United States continues to increase and is associated with health consequences such as type 2 diabetes, hypertension, atherosclerosis, and hyperlipidemia. Among many contributing factors to obesity, fructose may be one of the major reasons as it disrupts the antioxidant system thereby resulting in an accumulation of reactive oxidative species and leading to obese conditions. The enzyme, isocitrate dehydrogenase 2 (IDH2), reduces nicotinamide adenine dinucleotide phosphate from the TCA Cycle, hence might be implicated with not only energy metabolism but also cellular redox homeostasis. Therefore, the hypothesis was that IDH2 deficiency in mice would exacerbate hepatic lipid …

Insulin-Degrading Enzyme Is Not Secreted From Cultured Cells, Eun Suk Song, David W. Rodgers, Louis Hersh

Molecular and Cellular Biochemistry Faculty Publications

Insulin-degrading enzyme (IDE) functions in the catabolism of bioactive peptides. Established roles include degrading insulin and the amyloid beta peptide (Aβ), linking it to diabetes and Alzheimer’s disease. IDE is primarily located in the cytosol, and a longstanding question is how it gains access to its peptide substrates. Reports suggest that IDE secreted by an unconventional pathway participates in extracellular hydrolysis of insulin and Aβ. We find that IDE release from cultured HEK-293 or BV-2 cells represents only ~1% of total cellular IDE, far less than has been reported previously. Importantly, lactate dehydrogenase (LDH) and other cytosolic enzymes are released …

Dynamic Cycling Of T-Snare Acylation Regulates Platelet Exocytosis, Jinchao Zhang, Yunjie Huang, Jing Chen, Haining Zhu, Sidney W. Whiteheart

Molecular and Cellular Biochemistry Faculty Publications

Platelets regulate vascular integrity by secreting a host of molecules that promote hemostasis and its sequelae. Given the importance of platelet exocytosis, it is critical to understand how it is controlled. The t-SNAREs, SNAP-23 and syntaxin-11, lack classical transmembrane domains (TMDs), yet both are associated with platelet membranes and redistributed into cholesterol-dependent lipid rafts when platelets are activated. Using metabolic labeling and hydroxylamine (HA)/HCl treatment, we showed that both contain thioester-linked acyl groups. Mass spectrometry mapping further showed that syntaxin-11 was modified on cysteine 275, 279, 280, 282, 283, and 285, and SNAP-23 was modified on cysteine 79, 80, 83, …

Glycosaminoglycan Lyases In The Preparation Of Oligosaccharides, Alhumaidi B. Alabbas

Theses and Dissertations

Glycosaminoglycans are heterogeneous polysaccharides that mediate important biological functions. There has been considerable interest in deciphering the precise GAG sequences that are responsible for protein interactions. In fact, several GAG oligosaccharides have been discovered to date as targeting proteins with higher level of specificity. Yet, it has been difficult to develop GAG oligosaccharides as drugs. One of the key reasons for this state of art is that GAG synthesis is extremely challenging and is highly structure-specific. Thus, much of the biology and pharmacology of GAG remains unknown and unexploited to date.

An alternative approach is to prepare GAG oligosaccharides using …