7 research outputs found
Elucidating the mechanism of ferrocytochrome c heme disruption by peroxidized cardiolipin
The interaction of peroxidized cardiolipin with
ferrocytochrome c induces two kinetically and chemically
distinct processes. The first is a rapid oxidation of ferrocytochrome
c, followed by a slower, irreversible disruption
of heme c. The oxidation of ferrocytochrome c by peroxidized
cardiolipin is explained by a Fenton-type reaction.
Heme scission is a consequence of the radical-mediated
reactions initiated by the interaction of ferric heme iron
with peroxidized cardiolipin. Simultaneously with the
heme c disruption, generation of hydroxyl radical is
detected by EPR spectroscopy using the spin trapping
technique. The resulting apocytochrome c sediments as a
heterogeneous mixture of high aggregates, as judged by
sedimentation analysis. Both the oxidative process and the
destructive process were suppressed by nonionic detergents
and/or high ionic strength. The mechanism for generating
radicals and heme rupture is presented
Investigation of the Interaction between Mechanosynthesized ZnS Nanoparticles and Albumin Using Fluorescence Spectroscopy
In this paper, ZnS nanoparticles were bioconjugated with bovine serum albumin and prepared in a form of nanosuspension using a wet circulation grinding. The stable nanosuspension with monomodal particle size distribution (d50 = 137 nm) and negative zeta potential (−18.3 mV) was obtained. The sorption kinetics and isotherm were determined. Interactions between ZnS and albumin were studied using the fluorescence techniques. The quenching mechanism, describing both static and dynamic interactions, was investigated. Various parameters were calculated, including the quenching rate constant, binding constant, stoichiometry of the binding process, and accessibility of fluorophore to the quencher. It has been found that tryptophan, in comparison to tyrosine, can be closer to the binding site established by analyzing the synchronous fluorescence spectra. The cellular mechanism in multiple myeloma cells treated with nanosuspension was evaluated by fluorescence assays for quantification of apoptosis, assessment of mitochondrial membrane potential and evaluation of cell cycle changes. The preliminary results confirm that the nontoxic nature of ZnS nanoparticles is potentially applicable in drug delivery systems. Additionally, slight changes in the secondary structure of albumin, accompanied by a decrease in α-helix content, were investigated using the FTIR method after analyzing the deconvoluted Amide I band spectra of ZnS nanoparticles conjugated with albumin. Thermogravimetric analysis and long-term stability studies were also performed to obtain a complete picture about the studied system