pIMAGO-biotin enables detection and quantitation of phosphorylated proteins immobilized on a microplate using streptavidin-linked fluorophore at 550 nm absorbance for detection. The pIMAGO Fluor 550 kit includes pIMAGO-biotin reagent, streptavidin-linked Fluor 550 detection reagent (for 550 nm phosphoprotein detection), blocking buffer, pIMAGO buffer, high-binding 96-well adsorption plates and a control phosphoprotein.