2.8.1.8 [protein]-N6-(octanoyl)-L-lysine + an [Fe-S] cluster scaffold protein carrying a [4Fe-4S]2+ cluster + 2 S-adenosyl-L-methionine + 2 oxidized [2Fe-2S] ferredoxin + 6 H+ = [protein]-N6-[(R)-dihydrolipoyl]-L-lysine + an [Fe-S] cluster scaffold protein + 2 sulfide + 4 Fe3+ + 2 L-methionine + 2 5'-deoxyadenosine + 2 reduced [2Fe-2S] ferredoxin - - 2.8.1.8 [protein]-N6-(octanoyl)-L-lysine + an [Fe-S] cluster scaffold protein carrying a [4Fe-4S]2+ cluster + 2 S-adenosyl-L-methionine + 2 oxidized [2Fe-2S] ferredoxin + 6 H+ = [protein]-N6-[(R)-dihydrolipoyl]-L-lysine + an [Fe-S] cluster scaffold protein + 2 sulfide + 4 Fe3+ + 2 L-methionine + 2 5'-deoxyadenosine + 2 reduced [2Fe-2S] ferredoxin mechanism: sulfur is first inserted at C6 of octanoyl substrate to form an enzyme bound intermediate. In a subsequent rate determining step, the second sulfur atom is inserted at C8, suggesting an energy profile of the reaction reflecting the relative bond strengths of the primary and secondary C-H bonds to be cleaved at C8 and C6, resp. 671329