To gain deeper insight into the ArM's catalytic mechanism for oxidation reactions, we conducted steady-state kinetics and determined Michaelis-Menten saturation profiles. Our findings revealed that the rate of oxidation of TMB, kcat for Biot2 ─ FePP • Sav WT, was (344 ± 27) sec -1 with a Km value of (4.636 ± 0.2) mM with respect to H2O2 (K m H₂O₂ ). These values yield the catalytic efficiency (kcat/K m H₂O₂ ) of (7.42 ± 0.9) • 10 4 M -1 sec -1 . The catalytic rate of substrate oxidation by HRP and other peroxidases varies widely, even for the same protein, depending on the substrate. The most widely used kinetic parameters for comparing peroxidase activity among different catalysts/enzymes are kcat and kcat/K m H₂O₂ for a particular substrate. For TMB oxidation, the values of kcat and kcat/K m H₂O₂ for HRP are 3.48 • 10 3 sec -1 and 9.41 • 10 5 M -1 sec -1 , respectively. These are substantially larger than those for Biot2 ─ FePP • Sav WT. Nevertheless, the significant increase in catalytic activity observed when Biot2 ─ FePP was supported by the Sav scaffold suggests that catalytic activity may be improved through genetic optimization of Sav. • 10 3 sec -1 and (1.81 ± 0.05) • 10 6 M -1 sec -1 . These data compare favorably with the catalytic rate and efficiency of HRP for TMB oxidation. To the best of our knowledge, Biot2 ─ FePP