A possible model of hemoprotein-fatty acid peroxide complex demonstrated by electron spin resonance

Coordination reaction between linolenic-acid-hydroperoxide (LHPO) and chloro(5, 10, 15, 20-tetraphenyl)-porphyrinato iron (III), Fe(III)TPPCl, was investigated by means of ESR. ESR spectra of the ferric low-spin complex (g1 = 2.336, g2 = 2.174 and g3 = 1.929) was recorded for the mixture prepared by mixing Fe(III)TPPCl and LHPO at -78 degrees C in the presence of alkaline reagent. ESR line width of complex was broadened when 17O2 labeled LHPO was used for ESR measurement. In terms of the g-parameters of the ferric low-spin species, this complex was concluded to be Fe(III)TPP(-OCH3)(-OO-linolenic acid) type complex.