Method of screening substance interacting with ABC protein

A kit for measuring transporter activity of ABC (ATP Binding Cassette) protein, having a filter which can filtrate and separate a membrane fraction expressing ABC protein, labeled nucleoside triphosphate or its derivative, nucleoside diphosphate immobilized substance which forms a complex with nucleoside diphosphate by substituting phosphate ion of nucleoside triphosphate or its derivative and maintains the binding between nucleoside diphosphate and membrane protein, and at least unreacted labeled nucleoside triphosphate or its derivative.

A method for measuring transporter activity of ABC (ATP Binding Cassette) protein, wherein it has the following processes:

• a process of contacting a membrane fraction expressing ABC protein, labeled nucleoside triphosphate or its derivative, nucleoside diphosphate immobilized substance which forms a complex with nucleoside diphosphate by substituting phosphate ion of nucleoside triphosphate or its derivative and maintains the binding between nucleoside diphosphate and membrane protein, and a substrate of ABC protein;
• a process of cleaning the membrane fraction expressing the membrane protein with cleaning solvent, and separating at least unreacted labeled nucleoside triphosphate or its derivative by filtration through a filter;
• and a process of measuring the labeling on the filter and/or the labeling in the filtrate.