APS-5 is a chemiluminescent substrate based on 9,10-dihydropyridine. It is primarily used for ELISA detection of the complex between AP and alkaline phosphatase; the 9,10- structure in APS-5 can emit light continuously, stably, and efficiently under the action of AP.

It is very suitable for determining phosphatase activity solutions and phosphatase enzyme-linked immunoassays.