Pyrido[4,3-d]pyrimidine-2,4,7(1H,3H,6H)-trione, 1-(3-aminophenyl)-3-cyclopropyl-5-[(2-fluoro-4-iodophenyl)amino]-6,8-dimethyl-

1-(3-Aminophenyl)-3-cyclopropyl-5-((2-fluoro-4-iodophenyl)amino)-6,8-dimethylpyrido[4,3-d]pyrimidine-2,4,7(1H,3H,6H)-trione may be useful in the study of detectable probe comprising inhibitor component for determining formation of interaction interface between human MEK and KSR in physiological complex between MEK and KSR.