Isotachophoretic analysis of the pH dependent carrier properties of bovine serum albumin for rifamycin AF/013
✍ Scribed by Dr. Adam Csordas; Peter Josef Oefner; Georg Bartsch; Hans Grunicke; Giancarlo Lancini
- Publisher
- John Wiley and Sons
- Year
- 1986
- Tongue
- English
- Weight
- 635 KB
- Volume
- 7
- Category
- Article
- ISSN
- 0173-0835
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✦ Synopsis
Isotachophoretic analysis of the pH dependent carrier properties ofbovine serum albumin for rifamycin AF/O 13
The binding sites of bovine serum albumin for rifamycin AF/O13 were examined by means of analytical capillary isotachophoresis. At pH 7.5-7.9, there was only one binding site on non-defatted bovine serum albumin, while under the same conditions up to 20 binding sites could be detected on fatty acid-free albumin. In both cases the interaction became nonspecific above pH 8.0, resulting in a large number of rifamycin AF/O 13 molecules bound to albumin. Co-binding with oleic acid in vitro resulted in competition with all but the first high-affinity binding site for rifamycin AF/O13, corroborating the findings made with non-defatted albumin. Considering albumin as a model, the results might explain the conflicting reports about the number of binding sites of DNA-dependent RNA polymerases for rifamycin AF/O 13. Within a sharp pH-limit the highly specific binding becomes a nonspecific one. Moreover, the results suggest that the carrier function of bovine serum albumin might drastica!ly change in vivo, depending on the pH of physiological fluids.