binding assay - solid-phase overlay binding assay (Jun/03/2007 )

any one give me the idea what is this exactly ``solid-phase overlay binding assay``. may be too basic to yu all but it licked my brain help me please !!!
hontodayo!

---

I know SPE, solid-phase enzyme assay: You coat a suitable microtiter plate (ELISA plate) with a distinct protein, block, wash, and "overlay" with a potential protein binding partner; this binding partner should be labeled (radioactivity, fluorescence) or carry an enzyme activity to monitor with an enzyme assay; also, it may be detected with an Ab;

may also suitable to analyze receptor-ligand bindings

---