N-METHYLBENZOTHIAZOLE-RIFAMYCIN BINDING TO HUMAN PLASMA STUDIED BY DIFFERENTIAL SPECTROPHOTOMETRY
Author(s): Lu Run-zhong
Pages: 319-325+284
Year: 1983 Issue: 5
Journal: Chinese Journal of Antibiotics
Keyword: 力复霉素; 血浆蛋白; 差示分光光度法; 结合常数; 苯并噻唑; 浆浓度; 结合作用; 差示吸收度; 正常人血浆; 蛋白结合;
Abstract: The binding of N-methylbenzothiazole-rifamycin (R 75-1) to normal human plasma has been studied by means of differenti al spectrophotometry method. The differential absorption spectra for the interaction of several concentrations of R 75-1 and different levels of human plasma in phosphate buffer at pH 7.0 are presented and compared to those of the rifampicin plasma. Differential spectra of R 75-1-plasma were characterized by two positive peaks (380 and500 nm) in the wavelength range of 300 to 600 nm,while the spectra of rifampicin-plasma have no such a peak. The intensity of the differential absorption for the interaction of R 75-1 with human plasma is higher than that of rifampicin-plasma system.These results show that the differential spectra for the rifamycin derivative may be dependent on the characteristics of the C-3 substitue-nts. Binding parameters, including the nu- mber of binding sites and the binding constants were calculated for R 75-1 and plasma system at the antibiotic cocentration range of 1 to 3×10-5M, at different plasma concentrations. The binding constant for R 75-1 increased with increasing plasma concentration, whereas the number of binding sites on the plasma decreased with increasing plasma concentration. These results suggest that human plasma have different capacity and affinity sites for binding to the R 75-1.
Pages: 319-325+284
Year: 1983 Issue: 5
Journal: Chinese Journal of Antibiotics
Keyword: 力复霉素; 血浆蛋白; 差示分光光度法; 结合常数; 苯并噻唑; 浆浓度; 结合作用; 差示吸收度; 正常人血浆; 蛋白结合;
Abstract: The binding of N-methylbenzothiazole-rifamycin (R 75-1) to normal human plasma has been studied by means of differenti al spectrophotometry method. The differential absorption spectra for the interaction of several concentrations of R 75-1 and different levels of human plasma in phosphate buffer at pH 7.0 are presented and compared to those of the rifampicin plasma. Differential spectra of R 75-1-plasma were characterized by two positive peaks (380 and500 nm) in the wavelength range of 300 to 600 nm,while the spectra of rifampicin-plasma have no such a peak. The intensity of the differential absorption for the interaction of R 75-1 with human plasma is higher than that of rifampicin-plasma system.These results show that the differential spectra for the rifamycin derivative may be dependent on the characteristics of the C-3 substitue-nts. Binding parameters, including the nu- mber of binding sites and the binding constants were calculated for R 75-1 and plasma system at the antibiotic cocentration range of 1 to 3×10-5M, at different plasma concentrations. The binding constant for R 75-1 increased with increasing plasma concentration, whereas the number of binding sites on the plasma decreased with increasing plasma concentration. These results suggest that human plasma have different capacity and affinity sites for binding to the R 75-1.
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