ReACT (redox-activated chemical tagging) chemistry enables direct derivatization and fluorescence detection of S -adenosyl-L-homocysteine (SAH).

S -Adenosyl-L-homocysteine (SAH) is a universal byproduct and product inhibitor of the methyltransferase-catalyzed methylation reaction. Here based on ReACT (redox-activated chemical tagging) chemistry, direct derivatization and fluorescence measurement of SAH were achieved with features such as mild reaction conditions and simple operation.