Strong binding of ditrisarubicin B to DNA.
DNA binding characteristics of ditrisarubicin B were studied by the fluorescence titration technique. Ditrisarubicin B bound to calf thymus DNA with an affinity higher than any we have ever seen among anthracyclines. The apparent association constant (Kapp) of ditrisarubicin B was 2.36 X 10(8) M-1, which is 22.7 times larger than that of doxorubicin. The apparent number of binding sites (napp) of ditrisarubicin B per nucleotide of DNA was 0.164, and this value is identical with that of doxorubicin. Betaclamycin A, which has a trisaccharide chain at C-7 but no carbohydrate at C-10 in the aglycone, interacted with DNA to give a Kapp of 5.92 X 10(6) M-1 and napp of 0.178. These results suggest to us that the high affinity of ditrisarubicin B for DNA is caused by the existence of a glycosidic chain at C-10.
Kunimoto
S
S
Institute of Microbial Chemistry, Tokyo, Japan.
Takahashi
Y
Y
Uchida
T
T
Takeuchi
T
T
Umezawa
H
H
D000818:Animals; D018943:Anthracyclines; D000900:Anti-Bacterial Agents / Q000378:metabolism*; D000903:Antibiotics, Antineoplastic; D001665:Binding Sites; D002417:Cattle; D004247:DNA / Q000378:metabolism*; D009279:Naphthacenes / Q000378:metabolism; D013329:Structure-Activity Relationship
D018943:Anthracyclines; D000900:Anti-Bacterial Agents; D000903:Antibiotics, Antineoplastic; D009279:Naphthacenes; C042911:betaclamycin A; C039539:ditrisarubicin B; D004247:DNA