Patent ID: 7067270

Claim:
A method for detecting a target substance, which comprises steps of: (A) allowing a target substance to come into contact with a protein that binds to said target substance and that is labeled with a compound having a 6-membered ring represented by the following formula (1), so as to carry out a binding reaction; and (B) detecting the protein labeled with the compound having a 6-membered ring, which was bound to the target substance, by using an antibody that specifically binds to the compound having a 6-membered ring, wherein the antibody is conjugated to a detectable label, wherein R 1 and R 2 may be identical or different, and may independently represent a hydrogen atom, or alkyl group containing 1 to 6 carbon atoms, and the dotted line represents an atomic group necessary for forming a 6-membered ring, and wherein the compound having a 6-membered ring represented by the formula (1) is a theophylline compound.