TY - JOUR
T1 - Oxidation-reduction reactions of iron bleomycin in the absence and presence of DNA
AU - Goldstein, Sara
AU - Czapski, Gidon
PY - 1987
Y1 - 1987
N2 - Using the pulse radiolysis technique, we have demonstrated that bleomycin-Fe(III) is stoichiometrically reduced by CO2- to bleomycin-Fe(II) with a rate of (1.9 ± 0.2) × 108M-1s-1. In the presence of calf thymus DNA, the reduction proceeds through free bleomycin-Fe(III) and the binding constant of bleomycin-Fe(III) to DNA has been determined to be (3.8 ± 0.5) x 104 M-1. It has also been demonstrated that in the absence of DNA O2-1 reacts with bleomycin-Fe(III) to yield bleomycin-Fe(II)O2, which is in rapid equilibrium with molecular oxygen, and decomposes at room temperature with a rate of (700 ± 200) s-1. The resulting product of the decomposition reaction is Fe(III) which is bound to a modified bleomycin molecule. We have demonstrated that during the reaction of bleomycin-Fe(II) with O2, modification or self-destruction of the drug occurs, while in the presence of DNA no destruction occurs, possibly because the reaction causes degradation of DNA.
AB - Using the pulse radiolysis technique, we have demonstrated that bleomycin-Fe(III) is stoichiometrically reduced by CO2- to bleomycin-Fe(II) with a rate of (1.9 ± 0.2) × 108M-1s-1. In the presence of calf thymus DNA, the reduction proceeds through free bleomycin-Fe(III) and the binding constant of bleomycin-Fe(III) to DNA has been determined to be (3.8 ± 0.5) x 104 M-1. It has also been demonstrated that in the absence of DNA O2-1 reacts with bleomycin-Fe(III) to yield bleomycin-Fe(II)O2, which is in rapid equilibrium with molecular oxygen, and decomposes at room temperature with a rate of (700 ± 200) s-1. The resulting product of the decomposition reaction is Fe(III) which is bound to a modified bleomycin molecule. We have demonstrated that during the reaction of bleomycin-Fe(II) with O2, modification or self-destruction of the drug occurs, while in the presence of DNA no destruction occurs, possibly because the reaction causes degradation of DNA.
KW - Bleomycin
KW - DNA Damage
KW - Iron
KW - Radiolysis
KW - Superoxide
UR - http://www.scopus.com/inward/record.url?scp=0023554893&partnerID=8YFLogxK
U2 - 10.3109/10715768709065290
DO - 10.3109/10715768709065290
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C2 - 2462530
AN - SCOPUS:0023554893
SN - 1071-5762
VL - 2
SP - 259
EP - 270
JO - Free Radical Research
JF - Free Radical Research
IS - 4-6
ER -