Zur Wirkungsweise von Actinomycinen, III. Bindung von Actinomycin C an Nucleinsäuren und Nucleotide

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Abstract
Actinomycin forms complexes with deoxyribonucleic acid (DNA), nucleotides, nucleosides and purine bases. The complex is determined spectrophotometrically from the shifts in the absorption bands. Of the nucleosides, deoxyguanosine is especially active as an actinomycin complexing agent, and is far more efficient than guanosine. The stability of the actinomycin-DNA complex is independent of the ionic strength of the medium or the presence of Mg2*. The complex with deoxyguanosine is thermolabile; that with DNA is essentially more stable. Formaldehyde retards actinomycin-deoxyguanosine complex formation and decreases the stability of the complex bond, but has no effect on the DNA-actinomycin system. Presumably the NH2 groups of the bases are not concerned in the DNA-actinomycin complex formation, while the N-7 of deoxyguanosine is probably involved.