The cyclic voltammetric study of iron-tallysomycin in the absence and presence of DNA.
Cyclic voltammetric studies on iron-tallysomycin complexes have been conducted with and without the presence of calf thymus DNA. Fe(II)-TLM samples exhibit a cyclic voltammogram with only a reduction peak at -230 +/- 5 mV vs Ag/AgCl. The addition of DNA substrate causes the shift of this reduction peak to -140 +/- 10 mV vs Ag/AgCl. This large shift in the positive direction implies that the regeneration of Fe(II)-TLM through the reduction of Fe(III)-TLM is facilitated with the aid of DNA. It also implies that the metal-binding/oxygen-activation domain may be directly involved in the formation of iron-tallysomycin-DNA ternary complex. Air oxidation of Fe(II)-TLM produces an activated intermediate with the following CV characteristics, Ipc/Ipa = 0.90; delta E = 65 mV; Ereduction peak = -100 mV vs Ag/AgCl. Addition of DNA abolishes the redox peaks of this voltammogram, signifying inactivation of the activated species through reaction with substrate. Air oxidation of preformed Fe(II)-TLM-DNA complex did not give a discernable cyclic voltammogram, nor did preformed Fe(III)-TLM and Fe(III)-TLM-DNA samples.
Sun
J
J
Department of Chemistry, Duquesne University, Pittsburgh, Pennsylvania.
Solaiman
D K
DK
D000818:Animals; D000970:Antineoplastic Agents / Q000737:chemistry / Q000378:metabolism*; D001665:Binding Sites; D001761:Bleomycin / Q000737:chemistry / Q000378:metabolism* / Q000031:analogs & derivatives; D002417:Cattle; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D004247:DNA / Q000378:metabolism*; D004563:Electrochemistry; D005290:Ferric Compounds / Q000378:metabolism; D005296:Ferrous Compounds / Q000378:metabolism; D007501:Iron / Q000378:metabolism*; D010084:Oxidation-Reduction
D000970:Antineoplastic Agents; D005290:Ferric Compounds; D005296:Ferrous Compounds; D001761:Bleomycin; D004247:DNA; D007501:Iron; C016126:talisomycin