The　cytochrome　P411　enzyme　is　a　variant　of　cytochrome　P450(BM3)　from　Bacillus　megaterium　whose　active　site　is　an　iron　porphyrin　imine　([Fe(Por)(NH)](-))　specie.　This　specie　has　been　reported　to　successfully　promote　the　primary　amination　of　benzylic　and　allylic　C(sp(3))-H　bonds.　We　employed　density　functional　theory　to　study　the　electronic　structure　of　the　active　site　of　P411　enzyme　and　the　primary　amination　of　C-H　bond　reaction　that　it　catalyzes.　The　calculated　spin　densities　and　orbital　values　indicate　the　existence　of　resonance　in　this　specie;　namely,　[(por)(-OH)Fe-IV-N-2(-)-H](-)　＜-＞　[(por)(-OH)Fe-III-N　center　dot--H](-).　The　amination　of　C(sp(3))-H　bonds　consists　of　two　main　reaction　steps:　hydrogen-atom　abstraction　and　radical　recombination,　and　the　former　is　demonstrated　to　be　the　rate-determining　step.　Furthermore,　we　studied　the　regioselectivity　of　the　amination　of　primary　and　secondary　C(sp(3))-H　bonds.　Our　calculations　indicated　that　the　secondary　C(sp(3))-H　bonds　of　the　substrate　would　be　more　favored　for　the　activation　by　P411　enzyme.　These　results　provide　valuable　information　for　understanding　the　properties　and　selectivity　of　C-H/C-N　bond-activation　reactions　catalyzed　by　the　P411　enzyme　or　other　similar　enzymes.