scholarly journals Spectroscopic Studies on the Interaction of a Water-Soluble Cationic Porphyrin with Bovine Serum Albumin

2013 ◽  
Vol 36 (1-2) ◽  
pp. 21-26 ◽  
Author(s):  
Hamid Dezhampanah ◽  
Abdol-Khalegh Bordbar ◽  
Yadolahe Khodadusdt

The interaction of a water-soluble cationic porphyrin, Cobalt(III) 5, 10, 15, 20-tetrakis (1-methylpyridinium-4-yl) porphyrin [Co(III)TMPyP], with bovine serum albumin (BSA) has been studied in 1 mM phosphate buffer pH 7.0 containing 5 mM NaCl by UV-vis absorption, resonance light scattering (RLS) and fluorescence spectroscopies at 25°C. The results of RLS studies represent no aggregate formation of porphyrin in the surface of BSA and low tendency of this porphyrin for aggregate formation.The binding of porphyrin complex to BSA quenches fluorescence emission of BSA via a dynamic mechanism and the quenching process obeys a linear Stern-Volmer relationship. The values of Stern-Volmer constants, KSV, was determined nearly 105M−1, that depend on BSA concentration. The average aggregation number of BSA calculated from the analysis of fluorescence quenching data indicates that absence of any porphyrin induced aggregation of BSA due to its interaction with porphyrin complex. The binding of Co(III) TMPyP had no obvious effect on the molecular conformation of the protein. Electrostatic force played an important role in the binding due to the opposite charges on porphyrin and the protein.

2007 ◽  
Vol 11 (08) ◽  
pp. 556-565 ◽  
Author(s):  
A-Khalegh Bordbar ◽  
Hamid Dezhampanah ◽  
Mozaffar Asadi ◽  
Elham Safaei ◽  
Nasrin Sohrabi ◽  
...  

The equilibrium binding of the tetra-cationic complexes ( N , N ′, N ″, N ‴-tetra-methyltetra-2,3-pyridinoporphyrazinato)copper(II), ([ Cu (2,3- TMTPPA )]4+), ( N , N ′, N ″, N ‴-tetra-methyltetra-3,4-pyridinoporphyrazinato)copper(II), ([ Cu (3,4- TMTPPA )]4+), (( N , N ′, N ″, N ‴-tetra-methyltetra-3,4-pyridinoporphyrazinato)cobalt(II), ([ Co (3,4- TMTPPA )]4+) and (( N , N ′, N ″, N ‴-tetra-methyltetra-3,4-pyridinoporphyrazinato)zinc(II), ([ Zn (3,4- TMTPPA )]4+) with bovine serum albumin (BSA) has been studied in phosphate buffer pH = 7.0 and at various temperatures using multi-spectroscopy techniques. The results of resonance light scattering (RLS) studies represent no aggregate formation of porphyrazine in the surface of BSA and low tendency of these porphyrazine for aggregate formation. The binding constants and binding stoichiometries were determined by analyzing of optical absorption spectra of porphyrazine complexes at various concentration of BSA using SQUAD software. The results show that the best fitting corresponds to a 1:1 complex model between BSA and porphyrazines. The thermodynamic parameters were calculated by van't Hoff equation at various temperatures. The data indicate that the process is entropy driven suggesting that hydrophobic interactions play a considerable role in the complex formation. The binding of porphyrazine complexes to BSA quenches fluorescence emission of BSA via a dynamic mechanism and the quenching process obeys a linear Stern-Volmer relationship. The average aggregation number of BSA, which has been calculated from the analysis of fluorescence quenching data, indicates the absence of any porphyrazine induced aggregation of BSA due to its interaction with porphyrazine complexes. Fluorescence studies also indicate that porphyrazine is bound to site I of BSA placed in sub-domain IIA, where tryptophan 214 is located.


Antioxidants ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 1875
Author(s):  
Hajar Zarei ◽  
Mostean Bahreinipour ◽  
Yahya Sefidbakht ◽  
Shokouh Rezaei ◽  
Rouhollah Gheisari ◽  
...  

Radioprotective effects of vitamin C and vitamin E as a water-soluble and a lipid-soluble agent, respectively, were investigated at the molecular level during the imposition of gamma radiation-induced structural changes to bovine serum albumin (BSA) at the therapeutic dose of 3 Gy. Secondary and tertiary structural changes of control and irradiated BSA samples were investigated using circular dichroism and fluorescence spectroscopy. The preirradiation tests showed nonspecific and reversible binding of vitamins C and E to BSA. Secondary and tertiary structures of irradiated BSA considerably changed in the absence of the vitamins. Upon irradiation, α-helices of BSA transitioned to beta motifs and random coils, and the fluorescence emission intensity decreased relative to nonirradiated BSA. In the presence of the vitamins C or E, however, the irradiated BSA was protected from these structural changes caused by reactive oxygen species (ROS). The two vitamins exhibited different patterns of attachment to the protein surface, as inspected by blind docking, and their mechanisms of protection were different. The hydrophilicity of vitamin C resulted in the predominant scavenging of ROS in the solvent, whereas hydrophobic vitamin E localized on the nonpolar patches of the BSA surface, where it did not only form a barrier for diffusing ROS but also encountered them as an antioxidant and neutralized them thanks to the moderate BSA binding constant. Very low concentrations of vitamins C or E (0.005 mg/mL) appear to be sufficient to prevent the oxidative damage of BSA.


2013 ◽  
Vol 538 ◽  
pp. 301-304
Author(s):  
Yi Ping Zhong ◽  
Rui Bin Hong ◽  
Bin Bin Yin ◽  
Ping Liu ◽  
Wen Ji Deng

The water-soluble conjugated polyelectrolyte, poly[3-(1′-propyloxy-3′-sodium sulfonate) thiophene] (PTH-n3-SO3Na), was prepared. The interaction between the PTH-n3-SO3Na and bovine serum albumin (BSA) was investigated using UV-vis spectroscopy. It was found that the PTH-n3-SO3Na could be used as biosensor to detect BSA.


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