To examine the impact of non-specific hydrophobic interactions on the catalytic activity of Biot2 ─ FePP, we saturated the Sav WT protein with biotin before introducing the cofactor (Biot2 ─ FePP, Biot•Sav) to minimize the assembly of the ArM. Biot2 ─ FePP, Biot•Sav demonstrated similar catalytic efficiency as the free cofactor (Figure ). This confirms that the incorporation of Biot2 ─ FePP in the biotin-binding vestibule significantly contributes to the increase in the peroxidase activity of Biot2 ─ FePP • Sav WT. The initial rate of oxidation (V0) exhibited a linear increase with increasing concentration of Biot2 ─ FePP • Sav WT, suggesting that the reaction follows first-order kinetics with respect to the ArM, as depicted in Figure .