STUDY OF THE TRANSFORMATION OF NITROSYL IRON COMPLEX WITH N-ETHYLTHIOUREA LIGANDS IN MODEL BIOLOGICAL SYSTEMS

Author(s):  
Olesya Viktorovna Pokidova ◽  
◽  
Nina Sergeevna Emel’yanova ◽  
Alexander Vasilievich Kulikov ◽  
Alexander Ivanovich Kotelnikov ◽  
...  

The process of transformation of a mononuclear cationic complex with N-ethylthiourea ligands in Tris-HCl buffer, as well as in a reaction mixture with reduced glutathione and bovine serum albumin, has been studied. It was found that in the presence of glutathione, the complex dimer-izes, while its initial ligands are replaced by glutathione. In the presence of albumin, the decay product of the complex is coordinated with amino acid residues (Cys34 and His39) to form a protein-bound complex.

2021 ◽  
Vol 9 (3) ◽  
pp. 369-376
Author(s):  
O.A. Zav’yalova ◽  
◽  
Yu.A. Marsyanova ◽  
Yu.V. Abalenikhinа ◽  
A.F. Ishtulin ◽  
...  

BACKGROUND: The constancy of the protein composition of the body is one of the most important conditions for normal vital activity. Deviations in the content of the main bioelements, in particular, mixed valence metals, caused by environmental factors, improper nutrition and other factors, lead to various disorders. One of the properties of metals of mixed valence is the abil-ity to cause metal-catalyzed oxidation of proteins in joint action with active forms of oxygen. It seems interesting to study the oxidative modification of the amino acid residues of albumin and the change in its properties. AIM: To study the effect of reactive oxygen intermediates generated by the Fenton reaction in the presence of Fe2+ and Cu2+ on the oxidative modification of amino acid residues of bovine serum albumin. MATERIALS AND METHODS: The study was carried out on bovine serum albumin (BSA), which was incubated for 2 hours in a mixture of Fenton's reagents – FeSO4 + H2O2 and in a mixture of СuSO4 + H2O2. The quantitative protein content in the samples was determined with the bromcresol green reagent (Albumin-Olvex). The content of carbonyl derivatives of proteins was estimated by the method of R.L. Levine modified by E.E. Dubinina. The content of thiol groups in albumin samples from the control and experimental groups was determined by the Ellman method with DTNB (under non-denaturing conditions. RESULTS: The presented results demonstrate that under the action of Cu2+ ions, the formation of carbonyl derivatives of aliphatic amino acids of albumin is less than in the presence of Fe2+, which can be explained by the different degrees of albumin affinity to metals of variable valence. The rate of mobility of oxidatively modified albumin in polyacrylamide gel decreases, which is explained by protein aggregation due to bityrosine cross-links. CONCLUSION: Variable valence metals affect the modification of albumin. The change in the functional properties of the protein is of physiological significance, including the case of extracellular mobilization of iron and copper.


2021 ◽  
Author(s):  
Maria Bercea ◽  
Ioana-Alexandra Plugariu ◽  
Loredana Elena Nita ◽  
Simona Morariu ◽  
Robert Vasile Gradinaru

Molecules ◽  
2019 ◽  
Vol 24 (18) ◽  
pp. 3395 ◽  
Author(s):  
Iulia Matei ◽  
Cristina Maria Buta ◽  
Ioana Maria Turcu ◽  
Daniela Culita ◽  
Cornel Munteanu ◽  
...  

The formation and growth of gold nanoparticles (AuNPs) were investigated in pH 7 buffer solution of bovine serum albumin (BSA) at room temperature. The processes were monitored by UV-Vis, circular dichroism, Raman and electron paramagnetic resonance (EPR) spectroscopies. TEM microscopy and dynamic light scattering (DLS) measurements were used to evidence changes in particle size during nanoparticle formation and growth. The formation of AuNPs at pH 7 in the absence of BSA was not observed, which proves that the albumin is involved in the first step of Au(III) reduction. Changes in the EPR spectral features of two spin probes, CAT16 and DIS3, with affinity for BSA and AuNPs, respectively, allowed us to monitor the particle growth and to demonstrate the protective role of BSA for AuNPs. The size of AuNPs formed in BSA solution increases slowly with time, resulting in nanoparticles of different morphologies, as revealed by TEM. Raman spectra of BSA indicate the interaction of albumin with AuNPs through sulfur-containing amino acid residues. This study shows that albumins act as both reducing agents and protective corona of AuNPs.


1972 ◽  
Vol 50 (5) ◽  
pp. 563-573 ◽  
Author(s):  
Stephen J. Wetmore ◽  
Jacob A. Verpoorte

Two distinct fractions showing both β-N-acetyl-D-glucosaminidase (EC 3.2.1.30) and β-N-acetyl-D-galactosaminidase activity were isolated and purified from pig kidney. These preparations, which were designated A and B, were not stable during gel chromatography or prolonged dialysis. Final purifications of 600-fold for enzyme A and 440-fold for enzyme B were obtained.Gel electrophoresis and ultracentrifugation studies indicated heterogeneity in both preparations. The amino acid compositions of both preparations were very similar. Ultracentrifugation studies suggested the formation of subunits in the presence of 5 M guanidine–HCl and 1 mM dithiothreitol.A study of the enzymatic properties also showed great similarities between the two enzyme forms. Both enzymes had identical Michaelis–Menten constants of 1.88 mM for p-nitrophenyl-β-N-acetyl-D-glucosaminide and 0.38 mM for p-nitrophenyl-β-N-acetyl-D-galactosaminide. Although bovine serum albumin enhanced the activity of the enzymes it did not change the Km values. The pH-rate profiles of both enzymes with the substrate p-nitrophenyl-β-N-acetyl-D-glucosaminide showed two peaks. When p-nitrophenyl-β-N-acetyl-D-galactosaminide was used as substrate, only one peak was observed in the pH–rate profiles. However, in this case a distinct shoulder could be detected in these peaks. Heating at 50° destroyed the activities of both forms of the enzyme rapidly, but addition of bovine serum albumin protected against heat inactivation.


2006 ◽  
Vol 18 (7) ◽  
pp. 789 ◽  
Author(s):  
Chie Suzuki ◽  
Koji Yoshioka

The effects of glutamine, hypotaurine, taurine and premixed solutions of essential amino acids (EAA) and non-essential amino acids (NEAA) on in vitro development of porcine zygotes were evaluated. The effects of refreshing the medium and replacing polyvinyl alcohol (PVA) with bovine serum albumin (BSA) on embryonic development were also investigated. Porcine zygotes produced by in vitro maturation (IVM) and in vitro fertilisation (IVF) were cultured in porcine zygote medium (PZM), as the basal culture medium, for 5 days after IVF. The total number of cells in blastocysts was significantly increased by the addition of 2 mm glutamine to PZM, as was blastocyst yields after supplementation with 0.25 to 4 mm glutamine. Addition of 1.25 to 10 mm hypotaurine to PZM significantly increased blastocyst yields. Addition of 5 mm taurine to PZM significantly increased blastocyst yield, whereas taurine had no effect on blastocyst yield in cultures already containing 5 mm hypotaurine. Adding 1× EAA significantly increased the rate of blastocyst formation compared with no or 2× EAA, whereas 2× NEAA significantly increased the total cell numbers in blastocysts compared with no NEAA. Refreshing the medium at Day 3 had no effect on blastocyst yields, whereas medium change significantly reduced the total cell numbers in blastocysts. Adjusting the amino acid concentrations of a chemically defined medium can improve the developmental competence of porcine embryo.


1966 ◽  
Vol 21 (4) ◽  
pp. 305-313 ◽  
Author(s):  
G. Reske ◽  
F. Nimmerfall ◽  
J. Stauff

Interactions of eosin with three different substrates, β-lactoglobuline, bovine serum albumin and cysteine, in aqueous solutions of pH 7 under illumination with light of wavelengths 5200—5400 Å are investigated by changes in absorption spectrum characteristics, SH-group activities and phosphorescence intensities.Only with bovine serum albumin the major part of protein conversion, as shown by spectral changes and diminution of SH-groups due to eosin-sensitized photo-oxidation. In β-lactoglobuline an oxidizing photoreaction occurs, by which eosin is vanishing to the same degree as the protein shows loss of SH-groups and spectral alterations indicating attack on aromatic amino acid residues. There is no red shift of the eosin absorption band at 5170 Å as is observed in solutions of bovine serum albumin, where the intensity of phosphorscence is about 100 fold compared with the intensity obtained by solutions of β-lactoglobulin.The aerobic eosin photoreaction in solutions of β-lactoglobulin is faster than aerobic photobleaching of the dye. Still faster is its bleaching photoreaction with cysteine, which is nearly independent of oxygen.


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