Eisenberg M A, Hsiung S C
Antimicrob Agents Chemother. 1982 Jan;21(1):5-10. doi: 10.1128/AAC.21.1.5.
Actithiazic acid and alpha-methyldethiobiotin inhibited the conversion of dethiobiotin to biotin resting-cell suspensions of Escherichia coli. The concentrations which effected 50% inhibition were 0.45 and 1.1 microM for actithiazic acid and alpha-methyldethiobiotin, respectively. Cells grown in low concentrations of the two biotin antimetabolites showed derepression of the biotin A operon, as evidenced by the enhanced levels of the enzymes 7,8-diaminopelargonic acid aminotransferase and dethiobiotin synthetase. Derepression was not due to any direct regulatory effect of the antibiotics but was the consequence of the inhibition of the biotin synthetase enzyme; this inhibition prevented the intracellular concentration of biotin from reaching the levels required for normal regulation of the biotin A operon.
放线噻唑酸和α-甲基去硫生物素抑制了大肠杆菌静止细胞悬液中将去硫生物素转化为生物素的过程。对放线噻唑酸和α-甲基去硫生物素而言，产生50%抑制作用的浓度分别为0.45微摩尔和1.1微摩尔。在低浓度的这两种生物素抗代谢物中生长的细胞表现出生物素A操纵子的去阻遏，这可通过7,8-二氨基壬酸转氨酶和去硫生物素合成酶水平的升高得以证明。去阻遏并非由于抗生素的任何直接调节作用，而是生物素合成酶受到抑制的结果；这种抑制作用阻止了生物素在细胞内的浓度达到正常调节生物素A操纵子所需的水平。
