Kinetic analysis of rhodamines efflux mediated by the multidrug resistance protein (MRP1).
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Saengkhae C, Loetchutinat C, Garnier-Suillerot A
Kinetic analysis of rhodamines efflux mediated by the multidrug resistance protein (MRP1).
Biophys J. 2003 Sep;85(3):2006-14.
- PubMed ID
- 12944313 [ View in PubMed]
- Abstract
Characterization of rhodamine 123 as functional assay for MDR has been primarily focused on P-glycoprotein-mediated MDR. Several studies have suggested that Rh123 is also a substrate for MRP1. However, no quantitative studies of the MRP1-mediated efflux of rhodamines have, up to now, been performed. Measurement of the kinetic characteristics of substrate transport is a powerful approach to enhancing our understanding of their function and mechanism. In the present study, we have used a continuous fluorescence assay with four rhodamine dyes (rhodamine 6G, tetramethylrosamine, tetramethylrhodamine ethyl ester, and tetramethylrhodamine methyl ester) to quantify drug transport by MRP1 in living GLC4/ADR cells. The formation of a substrate concentration gradient was observed. MRP1-mediated transport of rhodamine was glutathione-dependent. The kinetics parameter, k(a) = V(M)/k(m), was very similar for the four rhodamine analogs but approximately 10-fold less than the values of the same parameter determined previously for the MRP1-mediated efflux of anthracycline. The findings presented here are the first to show quantitative information about the kinetics parameters for MRP1-mediated efflux of rhodamine dyes.
DrugBank Data that Cites this Article
- Drug Transporters
Drug Transporter Kind Organism Pharmacological Action Actions Rhodamine 6G Multidrug resistance-associated protein 1 Protein Humans UnknownSubstrateDetails Rhodamine 6G P-glycoprotein 1 Protein Humans UnknownSubstrateDetails