Microanalysis for MDR1 ATPase by high-performance liquid chromatography with a titanium dioxide column.

Area of Science:

• Biochemistry
• Pharmacology
• Analytical Chemistry

Background:

• Multidrug resistance protein 1 (MDR1) is crucial in cancer multidrug resistance and drug pharmacokinetics.
• MDR1 utilizes adenosine 5'-triphosphate (ATP) hydrolysis for drug transport, making ATPase activity assessment vital for drug interaction studies.

Purpose of the Study:

• To develop a novel, highly sensitive method for measuring MDR1 ATPase activity.
• To enable efficient drug screening by assessing drug interactions with purified MDR1.

Main Methods:

• Utilized high-performance liquid chromatography (HPLC) with a titanium dioxide column to quantify adenosine 5'-diphosphate (ADP) production.
• Established a linear detection range for ADP from 5 pmol to 10 nmol within a 2-minute assay.
• Significantly reduced the required amount of purified MDR1 to 0.5 ng per reaction.

Main Results:

• The novel HPLC method demonstrated high sensitivity for detecting subtle changes in MDR1 ATPase activity.
• Achieved a 20-fold reduction in purified MDR1 needed compared to conventional colorimetric assays.
• Validated the method's applicability for analyzing drug-induced alterations in MDR1 ATPase activity.

Conclusions:

• The developed HPLC-based assay offers a sensitive and efficient approach for measuring MDR1 ATPase activity.
• This method facilitates the study of drug interactions with MDR1, crucial for overcoming multidrug resistance.
• The technique is adaptable for assessing the ATPase activity of other proteins.