Our results reveal that ABTS is oxidized with a rate 1.6 times higher than that of HRP using Biot2 -FePP • Sav WT . In the presence of Biot2 ─ FePP • Sav S112E K121H, the peroxidase activity was further improved for ABTS oxidation: kcat = (5.7± 0.28) • 10 3 sec -1