As we have seen above, P450OleT does not proceed via a rebound mechanism, but prefers to accept one proton from His85, which occurs instantly and resets the cycle to the resting state. However, to substantiate the role of His85 that actually prevents the rebound step by associating a water molecule, we performed QMMM calculations for P450BSβ which performs hydroxylation in the WT, where the His85 residue is naturally replaced by Glutamine (Q). The optimized reactant-complex geometry (RC) shows an organized water channel, however, unlike in P450OleT, in P450BSβ the substrate stays far from the Q85 residue. In fact, the carboxylate group of the substrate does not interact with Q85 by any means. The pro-R hydrogen at the Cβ terminal is the closest hydrogen to the FeO moiety.