B - Blockers and in Vitro Dna Synthesis

The activity of DNA polymerase I from Saccharomyces cerevisiae is inhibited, in a dose-dependent fashion, by the oncogenic ~3-blocker 1-(2-nitro-3-methyl-phenoxy)3-tert-butylamino-propan-2-ol (ZAMI 1305) and by the non-oncogen ic 8-blockers 1-(2-nitro-5-methyl-phenoxy) -3ter t -buty lamino-propan-2-ol (ZAMI 1327), atenolol, and propranolol, the lat ter having the highest inhibiting activity. The inhibition is due to an interaction of the B-blockers with the free enzyme and with the enzymeDNA complex. The degree of inhibition is directly related to the hydrophobicity of the aromatic moiety and to the length and hydrophilicity of the aliphatic chain of the inhibitor. No relation seems to exist be tween the in vitro inhibition of yeast DNA polymerase I by B-blockers and their oncogenic activity.