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Full-Text Articles in Physical Sciences and Mathematics
Interaction Of Cationic Porphyrins With Dna, Ulrica Sehlstedt, Pamela Carter, Jerry Goodisman, James C. Dabrowiak, Seog K. Kim
Interaction Of Cationic Porphyrins With Dna, Ulrica Sehlstedt, Pamela Carter, Jerry Goodisman, James C. Dabrowiak, Seog K. Kim
Chemistry - All Scholarship
Utilizing linear dichroism (LD), circular dichroism (CD), and fluorescence energy transfer, the binding geometries of a series of Co3+-porphyrins and their free ligands were examined. The compounds studied were Co-meso-tetrakis(N-methylpyridinium-4-yl)porphyi(nC oTMPyP) and its free ligand (H2- TMPyP), Co-meso-tetrakis(N-n-butylpyridinium-4-yl)porphyrin( CoTBPyP) and its free ligand (H2TBPyP), and Co-meso-tetrakis(N-n-octylpyridinium-4-yl)porphyrin (CoTOPyP). The two non-metalloporphyrins exhibit negative LD, having angles of roughly 75' relative to the DNA helix axis. They also display negative CD and a significant contact energy transfer from the DNA bases. On the other hand, the three metalloporphyrins display orientation angles of roughly 45' between the porphyrin plane and the helix axis …
Formation Of O-Tyrosine And Dityrosine In Proteins During Radiolytic And Metal-Catalyzed Oxidation, Thomas G. Huggins, Mary C. Wells-Knecht, Nicholas A. Detorie, John W. Baynes, Suzanna R. Thorpe
Formation Of O-Tyrosine And Dityrosine In Proteins During Radiolytic And Metal-Catalyzed Oxidation, Thomas G. Huggins, Mary C. Wells-Knecht, Nicholas A. Detorie, John W. Baynes, Suzanna R. Thorpe
Faculty Publications
To evaluate their usefulness as chemical indicators of cumulative oxidative damage to proteins, we studied the kinetics and extent of formation of ortho-tyrosine (0-Tyr), dityrosine (DT), and dityrosine-like fluorescence (Ex = 3 17 nm, E,,, = 407 nm) in the model proteins RNase and lysozyme exposed to radiolytic and metalcatalyzed (H20z/Cu2+) oxidation (MCO). Although there were protein-dependent differences, o-Tyr, DT, and fluorescence increased coordinately during oxidation of the proteins in both oxidation systems. The contribution of DT to total dityrosine-like fluorescence in oxidized proteins varied from 2-10070, depending on the protein, type of oxidation, and extent of oxidative damage. In …
Oxidized Amino Acids In Lens Protein With Age: Measurement Of O-Tyrosine And Dityrosine In The Aging Human Lens, Mary C. Wells-Knect, Thomas G. Huggins, Daniel G. Dyer, Suzanne R. Thorpe, John W. Baynes
Oxidized Amino Acids In Lens Protein With Age: Measurement Of O-Tyrosine And Dityrosine In The Aging Human Lens, Mary C. Wells-Knect, Thomas G. Huggins, Daniel G. Dyer, Suzanne R. Thorpe, John W. Baynes
Faculty Publications
The concentrations of ortho-tyrosine (o-Tyr) and dityrosine (DT) were measured in noncataractous human lenses in order to assess the role of proteinoxidation reactions in the aging of lens proteins. The measurements were conducted by selected ion monitoring-gas chromatography/mass spectrometry using deuterium-labeled internal standards, which provided both high sensitivity and specificity for the quantitation of o-Tyr and DT. Between ages 1 and 78 years, the o-Tyr concentration in lens proteins varied from 0.3 to 0.9 mmol of o-Tyr/mol of Phe (n = 19), while DT ranged from 1 to 3 mumol of DT/mol of Tyr (n = 30). There were no …
Accumulation Of Maillard Reaction Products In Skin Collagen In Diabetes And Aging, Daniel G. Dyer, John A. Dunn, Suzanne R. Thorpe, Karen E. Bailie, Timothy L. Lyons, David R. Mccance, John W. Baynes
Accumulation Of Maillard Reaction Products In Skin Collagen In Diabetes And Aging, Daniel G. Dyer, John A. Dunn, Suzanne R. Thorpe, Karen E. Bailie, Timothy L. Lyons, David R. Mccance, John W. Baynes
Faculty Publications
To investigate the contribution of glycation and oxidation reactions to the modification of insoluble collagen in aging and diabetes, Maillard reaction products were measured in skin collagen from 39 type 1 diabetic patients and 52 nondiabetic control subjects. Compounds studied included fructoselysine (FL), the initial glycation product, and the glycoxidation products, N epsilon-(carboxymethyl) lysine (CML) and pentosidine, formed during later Maillard reactions. Collagen-linked fluorescence was also studied. In nondiabetic subjects, glycation of collagen (FL content) increased only 33% between 20 and 85 yr of age. In contrast, CML, pentosidine and fluorescence increased five-fold, correlating strongly with age. In diabetic patients, …
Maillard Reaction Products And Their Relation To Complications In Insulin-Dependent Diabetes Mellitus, David R. Mccance, Daniel G. Dryer, John A. Dunn, Karen E. Bailie, Suzanne R. Thorpe, John W. Baynes, Timothy J. Lyons
Maillard Reaction Products And Their Relation To Complications In Insulin-Dependent Diabetes Mellitus, David R. Mccance, Daniel G. Dryer, John A. Dunn, Karen E. Bailie, Suzanne R. Thorpe, John W. Baynes, Timothy J. Lyons
Faculty Publications
Glycation, oxidation, and browning of proteins have all been implicated in the development of diabetic complications. We measured the initial Amadori adduct, fructoselysine (FL); two Maillard products, N epsilon-(carboxymethyl) lysine (CML) and pentosidine; and fluorescence (excitation = 328 nm, emission = 378 nm) in skin collagen from 39 type 1 diabetic patients (aged 41.5 +/- 15.3 [17-73] yr; duration of diabetes 17.9 +/- 11.5 [0-46] yr, [mean +/- SD, range]). The measurements were related to the presence of background (n = 9) or proliferative (n = 16) retinopathy; early nephropathy (24-h albumin excretion rate [AER24] > or = 20 micrograms/min; n …
Flow Injection Analysis Concepts And Misconceptions, Julian Tyson
Flow Injection Analysis Concepts And Misconceptions, Julian Tyson
Chemistry Department Faculty Publication Series
Aspects of definitions of analytical chemistry and flow injection analysis are discussed. The driving force in analytical research of cost-effectiveness is identified and the characteristics of flow injection examined. Basic concepts of fluid flow relevant to flow injection are explained and some common misconceptions concerning the magnitude of various phenomena examined. The implications fa the design of manifolds for high sensitivity are evaluated and some practical problems addressed. Novel features of FI, which take advantages of the kinetic nature of suitable processes, are identified and illustrated by some of Professor Ishibshi's work.
Determination Of Total Mercury In Waters And Urine By Flow Injection Atomic Absorption Spectrometry Procedures Involving On- And Off-Line Oxidation Of Organomercury Species, Julian Tyson, C P. Hanna, S Mcintosh
Determination Of Total Mercury In Waters And Urine By Flow Injection Atomic Absorption Spectrometry Procedures Involving On- And Off-Line Oxidation Of Organomercury Species, Julian Tyson, C P. Hanna, S Mcintosh
Chemistry Department Faculty Publication Series
No abstract provided.
An Experiment Using Time-Based Detection In Flow Injection Analysis, Mary K. Carroll, Julian Tyson
An Experiment Using Time-Based Detection In Flow Injection Analysis, Mary K. Carroll, Julian Tyson
Chemistry Department Faculty Publication Series
We present a laboratory experiment, suitable for implementation in analytical chemistry courses at the undergraduate level, that demonstrates the utility of time-based measurements with doublet peaks in flow injection analysis. The measurements are taken with an instrument that incorporates a simple solid-state detector, which has as its source a light-emitting diode (LED) and as its detecting element a photodiode (PD). The system studied here is a simple acid-base titration. The experiment could be adapted to any number of chemical reactions that result in a product that absorbs light of the LED wavelength significantly.
Electrochemical Studies Of Swelling And Shrinking Of Clay Films, Jia Du
Electrochemical Studies Of Swelling And Shrinking Of Clay Films, Jia Du
Master's Theses
No abstract provided.
A Clay Modified Electrode For Ion-Exchange Voltammetry, Thaddeus S. Wielgos
A Clay Modified Electrode For Ion-Exchange Voltammetry, Thaddeus S. Wielgos
Master's Theses
No abstract provided.
Reactions Of 1-Triptycyl Carbinol And Bis-(1-Triptycyl)-Carbinol, Bryce Arthur Milleville
Reactions Of 1-Triptycyl Carbinol And Bis-(1-Triptycyl)-Carbinol, Bryce Arthur Milleville
Master's Theses
No abstract provided.
Nmr Study Of Na+-H+ And Na+-Li+ Exchange In Human Erythrocytes, Suilan Mo
Nmr Study Of Na+-H+ And Na+-Li+ Exchange In Human Erythrocytes, Suilan Mo
Master's Theses
No abstract provided.
Aspects Of Gold Recovery From An Indigenous Ore, Cormac Patrick Mcnamee
Aspects Of Gold Recovery From An Indigenous Ore, Cormac Patrick Mcnamee
Masters
This project involved the investigation into the basic electrochemistry of the thiourea-formamidine disulphide redox couple and an estimation of the formal potential, Eo1 for the couple. By carrying out optimisation experiments on the leaching of gold from an ore sample from the Avoca mine in Co. Wicklow, the optimum leaching conditions were determined for maximum gold extraction. The effects of various organic and inorganic species on the adsorption of gold onto activated carbon and modified peat were investigated with the use of factorial designed experiments. The Langmuir Isotherm model was applied to estimate the capacity of the carbon for these …