“…Since CYP450s possess a characteristic active site with an Fe III -heme center as the fulcrum, and given the paramagnetic nature of the iron, not only in the resting state of the enzyme but also in several intermediates generated during the CYP450 catalytical cycle, EPR spectroscopy lends itself as a very suitable technique to characterize and analyze this system [ 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 ]. In our previous work [ 32 , 33 ], we carried out a study on CYP116B5hd, where we analyzed the g -values according to the electronic model for low-spin Fe III by Taylor [ 34 , 35 ] and compared our results with those obtained for other classical (monooxygenase-like) CYP450s, such as CYP102A1 (CYPBM3), and more exotic (peroxygenase-like) CYP450s, such as CYP152B1, CYP152K6, and CYP152L1. From this comparison, it was concluded that the electronic state of the enzyme was very much like the classic P450, determined by the active site in the close proximity of iron.…”