(1) protoporphyrin IX@mitochondrial matrix+Fe_super_2+_endsuper_@mitochondrial matrix - FECH@mitochondrial matrix -> ferroheme b@mitochondrial matrix+H_super_+_endsuper_@mitochondrial matrix
(2) FECH@mitochondrial matrix+NO@mitochondrial matrix -> FECH@mitochondrial matrix
(3) FECH@mitochondrial matrix -> FECH@mitochondrial matrix