A5041183076- Metal-Catalyzed Oxygenation Mechanisms
- Amino Acid Enzymes and Metabolism
- Mass Spectrometry Techniques and Applications
- Porphyrin Metabolism and Disorders
- Polyamine Metabolism and Applications
- Drug Transport and Resistance Mechanisms
- Pharmacogenetics and Drug Metabolism
- Enzyme Structure and Function
- Metabolism and Genetic Disorders
- Microbial metabolism and enzyme function
- Protein Structure and Dynamics
- Biochemical effects in animals
- RNA Research and Splicing
- RNA modifications and cancer
- Biotin and Related Studies
- Biochemical Analysis and Sensing Techniques
- Protein Hydrolysis and Bioactive Peptides
- Photosynthetic Processes and Mechanisms
- GABA and Rice Research
- Trypanosoma species research and implications
- Research on Leishmaniasis Studies
- RNA and protein synthesis mechanisms
- Parasites and Host Interactions
- Microbial bioremediation and biosurfactants
University of South Carolina Aiken
2016-2020
The University of Texas Health Science Center at San Antonio
2012-2014
Washington State University
2010
The mechanism of N-dealkylation mediated by cytochrome P450 (P450) has long been studied and argued as either a single electron transfer (SET) or hydrogen atom (HAT) from the amine to oxidant P450, reputed iron-oxene. In our study, tertiary anilinic N-oxides were used oxygen surrogates directly generate P450-mediated that is capable N-dealkylating dimethylaniline derived donation. These employed probe generated reactive species subsequent distinguish between HAT SET mechanisms. addition...
The flavoprotein Berberine Bridge Enzyme (BBE) catalyzes the regioselective oxidative cyclization of (S)-reticuline to (S)-scoulerine in an alkaloid biosynthetic pathway. A series solvent and substrate deuterium kinetic isotope effect studies were conducted discriminate between a concerted mechanism, which deprotonation phenol occurs before or during transfer hydride from flavin cofactor cyclization, stepwise results formation methylene iminium ion intermediate that is subsequently cyclized....
Analytical ultracentrifugation has been used to analyze the oligomeric structure of isolated regulatory domain phenylalanine hydroxylase. The protein exhibits a monomer-dimer equilibrium with dissociation constant ~46 μM; this value is unaffected by removal 24 N-terminal residues or phosphorylation Ser16. In contrast, binding (Kd = 8 μM) stabilizes dimer. These results suggest that dimerization hydroxylase linked allosteric activation enzyme.
Significance The RNA lariat debranching enzyme Dbr1 cleaves the 2′,5′-phosphodiester linkages in intron lariats generated during pre-mRNA splicing. is central to metabolism because its activity required for turnover and production of small nucleolar RNAs microRNAs encoded intronic RNA. Here, kinetics Dbr1-mediated a synthetic substrate are measured by using apoenzyme reconstituted with various divalent cations. results suggest Fe Zn preferred cofactors. Structures binuclear catalytic mutant...
Phenylalanine hydroxylase (PheH) catalyzes the key step in catabolism of dietary phenylalanine, its hydroxylation to tyrosine using tetrahydrobiopterin (BH(4)) and O(2). A complete kinetic mechanism for PheH was determined by global analysis single-turnover data reaction PheHΔ117, a truncated form enzyme lacking N-terminal regulatory domain. Formation productive PheHΔ117-BH(4)-phenylalanine complex begins with rapid binding BH(4) (K(d) = 65 μM). Subsequent addition phenylalanine binary...
Phenylalanine hydroxylase (PheH), a liver enzyme that catalyzes the hydroxylation of excess phenylalanine in diet to tyrosine, is activated by phenylalanine. The lack activity at low levels has been attributed N-terminus protein's regulatory domain acting as an inhibitory peptide blocking substrate access active site. location site which binds activate unknown, and both catalytic separate N-terminal have proposed. Binding catecholamines active-site iron was used probe accessibility Removal...
The flavoprotein L-hydroxynicotine oxidase (LHNO) catalyzes an early step in the bacterial catabolism of nicotine. Although structure enzyme establishes that it is a member monoamine family, LHNO generally accepted to oxidize carbon-carbon bond pyrrolidine ring substrate and has been proposed catalyze subsequent tautomerization hydrolysis initial oxidation product yield 6-hydroxypseudooxynicotine [Kachalova, G., et al. (2011) Proc. Natl. Acad. Sci. U.S.A. 108, 4800-4805]. Analysis from...
Continuous-flow mass spectrometry (CFMS) was used to monitor the products formed during initial 0.25-20 s of reactions catalyzed by flavoprotein N-acetylpolyamine oxidase (PAO) and pterin-dependent enzymes phenylalanine hydroxylase (PheH) tyrosine (TyrH). N,N'-Dibenzyl-1,4-diaminobutane (DBDB) is a substrate for PAO which amine oxidation rate-limiting. CFMS reaction showed formation an imine due exo-carbon-nitrogen bond. Nonenzymatic hydrolysis benzaldehyde N-benzyl-1,4-diaminobutane;...