Radioligand Assays and Non-specific Binding? - Non specific binding, various drugs (Feb/16/2009 )

Why is it important to define non specific binding with different drugs when first establishing a radioligand binding assay and why do most investigators choose to use a different compound from the one being investigated?

Does this have anything to do with dissociation constants?

any help would be appreciated!?

It is not "non-specific binding" that is being tested. It is cross reactivity. The parameter being tested is the specificity of the ab. With small MW drugs the testing is by competition. Drug labelled conjugate competes for binding with the drug in the sample.

If the specificity of the ab is poor other drugs of similar structure will be bound which may also include the breakdown product of the drug.

Another factor the comes into play is the site at which the conjugation takes place. This may influence which compounds will react/'compete for binding.

hope this helps.