抄録
Though toxopyrimidyl acetylpyridine (TXP-AcP) is the condensation product of 3-acetylpyridine (3-AcP) with toxopyrimidine (TXP) its injection causes mice to show symptoms quite different from those aroused by the injection of its components. It has no inhibitory action upon vitamin B_6-dependent enzymes contrary to TXP. The toxic action of TXP-AcP upon yeast alcohol dehydrogenase (ADH) is a little stronger than that of 3-AcP. But the inhibitory action on pyridine enzyme would not explain the mechanism of the toxic action of TXP-AcP on mice because the inhibition on ADH is not prevented by phenobarbital while the death by the injectin of TXP-AcP is fully prevented by phenobarbital. As to cytochrome c oxidase it is inhibited by TXP-AcP but to much weaker extent than by KCN, the ratio of inhibition being below 1 : 100 in molar concentration. As the ratio in lethal dose in mice, however, is 1 : 18 (KCN : TXP-AcP), the mechanism of the lethal intoxication seemed to be other than the inhibition of the cytochrome c oxidase system.
