Investigation on the peroxidase-mimic activity of adenine phosphate and its applications

The peroxidase-like activity of adenine phosphate (AP) was investigated for the first time using chromogenic substrate 3, 3′, 5, 5′-tetramethylbenzidine (TMB) in the presence of H 2 O 2 . Effects of different reaction conditions, including pH, temperature, AP concentration and incubation time on the catalytic property of AP, were investigated. The peroxidase-like activity of AP complies with Michaelis-Menten kinetics, and the calculated kinetic parameter ( K m , 0.038 mM) of AP catalysis exhibits higher affinity to H 2 O 2 than natural horseradish peroxidase and some of the other small-molecule peroxidase mimics. The radical scavenging results confirm that hydroxyl radical (•OH) is the active specie of catalytic process. Based on the excellent catalytic performance of AP, a facile colorimetric method for the H 2 O 2 and ascorbic acid detection with good sensitivity and selectivity was established at the linear ranges of 2.0–50.0 μM and 20.0–70.0 μM, respectively. In addition, the developed method was applied to detect H 2 O 2 and ascorbic acid in practical samples. In short, this work will not only broaden the understanding of biological function of AP, but also facilitate the development of new category of small-molecule enzyme mimics.