ISSN:
0173-0835
Keywords:
Chemistry
;
Biochemistry and Biotechnology
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Biology
,
Chemistry and Pharmacology
Notes:
The binding sites of bovine serum albumin for rifamycin AF/013 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/013 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/013, 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 rifamy cin AF/013. 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 drastically change in vivo, depending on the pH of physiological fluids.
Additional Material:
8 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/elps.1150071004
