Demonstration that the temporary sequestering of adventitious iron accounts for the inhibition of microsomal lipid peroxidation by bleomycin A₂

One of the manifestations of the interaction of bleomycin with the microsomal mixed-function oxidase system is an inhibition of NAPDH-dependent, reactive oxygen-mediated lipid peroxidation. The results of this investigation demonstrate that this effect by bleomycin can be attributed to the sequestering of adventitious iron. However, as a result of the microsome-catalyzed, iron-facilitated activation of bleomycin and the concomitant spontaneous decay of the activated bleomycin intermediate, iron can apparently no longer be bound by the bleomycin molecule; consequently, the inhibition of microsomal lipid peroxidation by bleomycin is only temporary.