[Study on the interaction of PTB and serum albumin by fluorescence method].
A molecular spectroscopic investigation of the interaction of phenacyl thiazolium bromide (PTB) and bovine serum albumin (BSA) or human serum albumin (HSA) is reported employing fluorescence quenching techniques. It is determined that the maximal excitation wavelength is 280 nm for BSA solution, and 290 nm for HAS solution. When PTB was added into these solutions gradually, the emission peaks were decreased obviously, which are typical quenching phenomena. The results obtained reveal that there is a medium-intensity binding affinity for PTB with HSA and BSA. At 15 degrees C, the binding constants of PTB and BSA (HSA) are 3.66 x 10(3) and 3.83 x 10(3), and the numbers of binding sites are 1.02 and 1.06 respectively. At 37 degrees C, the binding constants of PTB and BSA (HSA) are 3.58 x 10(3) and 3.35 x 10(3), and the numbers of binding sites are 0.95 and 0.87 respectively. According to the thermodynamic parameters, the main sort of the binding force between the drug and BSA or HSA was electrostatic force. Based on the Föster non-radiation energy transfer theory, it could be acquired that the distance between BSA or HSA and PTB is 7.5 or 7.9 nm. According to the crystal structure of serum albumin, it can be speculated that subdomain II A was the binding sites for the interaction of PTB and serum albumin, which is the region near Try214.
Chen
Yan-hua
YH
College of Pharmacology, Jilin University, Changchun 130021, China.
Bu
Feng-quan
FQ
Hu
Xiu-li
XL
Liu
Zhi-qiang
ZQ
Liu
Zhong-ying
ZY
Liu
Jing-ying
JY
Zhou
Qiu-li
QL
D000818:Animals; D002417:Cattle; D004735:Energy Transfer; D005453:Fluorescence; D006801:Humans; D007004:Hypoglycemic Agents / Q000737:chemistry*; D011485:Protein Binding; D012709:Serum Albumin / Q000737:chemistry*; D012710:Serum Albumin, Bovine / Q000737:chemistry*; D013050:Spectrometry, Fluorescence / Q000379:methods*; D013816:Thermodynamics; D013844:Thiazoles / Q000737:chemistry*
D007004:Hypoglycemic Agents; C101705:N-phenacylthiazolium bromide; D012709:Serum Albumin; D013844:Thiazoles; D012710:Serum Albumin, Bovine