[Determination of the binding constant of bovine serum albumin and gatifloxacin using affinity capillary electrophoresis].
The interaction between bovine serum albumin (BSA) and gatifloxacin (GT) was investigated using affinity capillary electrophoresis (ACE) method, mobility-shift method. The mobility ratio of the internal standard and the sample was used to calculate the binding constant K(b) of bovine serum albumin and gatifloxacin. At first, 20 mmol/L, pH 7.4 sodium phosphate buffer solution (PBS) added with 0 - 1 000 micromol/L GT as running buffer was used, BSA as the sample was used. K(b) calculated from this experiment was 4.4 x 10(4) L/mol. Then 0 - 12.5 micromol/L BSA was used as an additive to do the ACE experiment, the K(b) obtained was 4.2 x 10(4) L/mol. The two values matched well with each other. In order to improve the shape of the peak and restrain the adsorption of BSA to the internal wall of the quartz column, in the second method, 0.25 mol/L Gly and 0.5 mmol/L ethylenediamine tetracetate (EDTA) were added to the running buffer, and 0.5% sodium dodecyl sulfate (SDS) solution was used to rinse the column. Satisfactory effect was obtained. The K(b) from fluorescence method was also calculated with a value of 2.7 x 10(4) L/mol. This work demonstrated that the determination of the binding constant by ACE is simple with high performance.
Yao
Zhi
Z
School of Pharmaceutical Science and Technology, Tianjin University, Tianjin 300072, China. valleyyao@yahoo.com.cn
Zhang
Haobo
H
Wu
Yi
Y
Guo
Huaizhong
H
D000818:Animals; D002417:Cattle; D019075:Electrophoresis, Capillary / Q000379:methods*; D024841:Fluoroquinolones / Q000378:metabolism*; D000077734:Gatifloxacin; D011485:Protein Binding; D012710:Serum Albumin, Bovine / Q000378:metabolism*
D024841:Fluoroquinolones; D012710:Serum Albumin, Bovine; D000077734:Gatifloxacin