Electrochemical Investigation of Cysteamine at Carbon Fiber Microdisk Electrode

El-Hallag, Ibrahim S.; Al‐Youbi, Abdulrahman O.; Obaid, Abdullah Y.; El‐Mossalamy, E.H.; El‐Daly, Samy A.; Asiri, Abdullah M.

doi:10.4067/s0717-97072011000400003

Cited by 8 publications

(5 citation statements)

References 29 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…S6, A and B ), with higher reductant concentrations leading to faster rates. In general, the rates with MEA were slower than those with an equivalent concentration of DTT, which is consistent with the stronger reduction potential of DTT ( 32 , 33 ). The type and concentration of reducing agent played a less significant role when the reaction was performed with IgG1 C→S .…”

Section: Resultssupporting

confidence: 72%

Kinetic mechanism of controlled Fab-arm exchange for the formation of bispecific immunoglobulin G1 antibodies

Goulet

Orcutt

Zwolak

et al. 2018

Journal of Biological Chemistry

View full text Add to dashboard Cite

Bispecific antibodies (bsAbs) combine the antigen specificities of two distinct Abs and demonstrate therapeutic promise based on novel mechanisms of action. Among the many platforms for creating bsAbs, controlled Fab-arm exchange (cFAE) has proven useful based on minimal changes to native Ab structure and the simplicity with which bsAbs can be formed from two parental Abs. Despite a published protocol for cFAE and its widespread use in the pharmaceutical industry, the reaction mechanism has not been determined. Knowledge of the mechanism could lead to improved yields of bsAb at faster rates as well as foster adoption of process control. In this work, a combination of Förster resonance energy transfer (FRET), nonreducing SDS-PAGE, and strategic mutation of the Ab hinge region was employed to identify and characterize the individual steps of cFAE. Fluorescence correlation spectroscopy (FCS) was used to determine the affinity of parental (homodimer) and bispecific (heterodimer) interactions within the CH3 domain, further clarifying the thermodynamic basis for bsAb formation. The result is a clear sequence of events with rate constants that vary with experimental conditions, where dissociation of the K409R parental Ab into half-Ab controls the rate of the reaction.

show abstract

Section: Resultssupporting

confidence: 72%

Kinetic mechanism of controlled Fab-arm exchange for the formation of bispecific immunoglobulin G1 antibodies

Goulet

Orcutt

Zwolak

et al. 2018

Journal of Biological Chemistry

View full text Add to dashboard Cite

show abstract

“…In this work we want to probe the Fe(II)/(I) redox potential as an activity descriptor for the oxidation of cysteamine. Cysteamine is a biologically relevant molecule [30] and active electrodes for the electrooxidation of cysteamine can potentially serve as electrochemical sensors for detecting this biologically important molecule [31][32][33][34][35][36][37][38]. Cysteamine is an aminothiol which has the formula HSCH 2 CH 2 NH 2 .…”

Section: Introductionmentioning

confidence: 99%

Probing the Fen+/Fe(n−1)+ redox potential of Fe phthalocyanines and Fe porphyrins as a reactivity descriptor in the electrochemical oxidation of cysteamine

Silva

Calderón

Páez

et al. 2018

Journal of Electroanalytical Chemistry

View full text Add to dashboard Cite

The M n + /M (n − 1)+ redox potential of MN4 macrocyclic molecular catalysts is a very good reactivity descriptor for several electrochemical reactions. One important feature about this reactivity descriptor is that it can be determined experimentally under the same conditions of the kinetic measurements in contrast to other descriptors like intermediate binding energies that are estimated from DFT calculations. However a linear correlation between both descriptors seems to exist. Plots of activity as (logj) E at constant E versus the M n + /M (n − 1)+ redox potential gives volcano correlations. Another important aspect about this parameter is that it is possible to tune the M n + /M (n − 1)+ redox potential of the MN4 catalyst by manipulating the structure of the macrocyclic complex and tailoring the electron-withdrawing power of the ligands to obtain the maximum activity. In this work we have probed the redox potential as a reactivity descriptor for the oxidation of cysteamine studying a series of substituted Fe phthalocyanines and Fe porphyrins adsorbed on glassy carbon and pyrolytic graphite in alkaline media. As expected the catalytic activity of these FeN4 species varies strongly with the Fe (II)/(I) redox potential of the different Fe phthalocyanines and a plot of activity as (logj) E versus E°Fe(II/I) gives a volcanoshaped correlation so a formal potential value exists for which the highest activity can be achieved demonstrating that the formal potential of the complexes seems to be an universal reactivity descriptor for electrochemical reactions.

show abstract

“…Therefore, to accelerate this reaction, we envisioned employing 9-fluorenone (9-FL) as an inexpensive photocatalyst . Although the oxidation potential of the T 1 exited state of 9-FL (+0.96 V versus SCE) would suffice to oxidize cysteamine (+0.92 V versus SCE), it might also act via energy transfer catalysis. − However, it is difficult to distinguish the two pathways experimentally.…”

Section: Resultsmentioning

confidence: 99%

Synthesis of Thiomorpholine via a Telescoped Photochemical Thiol–Ene/Cyclization Sequence in Continuous Flow

Steiner

Nelson

Dallinger

et al. 2022

Org. Process Res. Dev.

View full text Add to dashboard Cite

A procedure for the continuous flow generation of thiomorpholine in a two-step telescoped format was developed. The key step was the photochemical thiol–ene reaction of cysteamine hydrochloride and vinyl chloride as low-cost starting materials. This reaction could be conducted under highly concentrated (4 M) conditions using a low amount (0.1–0.5 mol %) of 9-fluorenone as the photocatalyst, leading to the corresponding half-mustard intermediate in quantitative yield. Thiomorpholine was subsequently obtained by base-mediated cyclization. The robustness of the process was demonstrated by performing the reaction for 7 h (40 min overall residence time), isolating the desired thiomorpholine via distillation.

show abstract

Electrochemical Investigation of Cysteamine at Carbon Fiber Microdisk Electrode

Cited by 8 publications

References 29 publications

Kinetic mechanism of controlled Fab-arm exchange for the formation of bispecific immunoglobulin G1 antibodies

Kinetic mechanism of controlled Fab-arm exchange for the formation of bispecific immunoglobulin G1 antibodies

Probing the Fen+/Fe(n−1)+ redox potential of Fe phthalocyanines and Fe porphyrins as a reactivity descriptor in the electrochemical oxidation of cysteamine

Synthesis of Thiomorpholine via a Telescoped Photochemical Thiol–Ene/Cyclization Sequence in Continuous Flow

Contact Info

Product

Resources

About