Yamada R H, Wakabayashi Y, Iwashima A
Acta Vitaminol Enzymol. 1984;6(4):289-93.
Intraperitoneal administration of isoniazid (IN), an antituberculous drug, to mice at a dose of 100 mg/kg body weight induced significant inhibition of serum aspartate aminotransferase (AAT) in several hours. The original activity was not restored readily by in vitro treatment of the sera with pyridoxal phosphate (PLP), in contrast to the rapid activation, by the same treatment, of apoAAT in the sera from control mice. Prolonged incubation with PLP prior to the assay was required to restore most of the lost activity. Serum AAT activity enhanced by experimental and the reversal of the inhibition similarly required prolonged incubation with PLP. The results suggest the possibility that human serum AAT activity measured for clinical diagnosis may be underestimated in cases of IN overdose even if the conditions for in vitro PLP treatment of samples are sufficient for conversion of the apoenzyme to the holoenzyme.
给小鼠腹腔注射抗结核药物异烟肼（IN），剂量为100毫克/千克体重，数小时内可显著抑制血清天冬氨酸转氨酶（AAT）。与用相同处理快速激活对照小鼠血清中的脱辅基AAT相反，用磷酸吡哆醛（PLP）对血清进行体外处理不能轻易恢复原始活性。在测定前用PLP长时间孵育才能恢复大部分丧失的活性。实验增强的血清AAT活性以及抑制的逆转同样需要用PLP长时间孵育。结果表明，即使样品体外PLP处理条件足以将脱辅基酶转化为全酶，在IN过量的情况下，用于临床诊断的人血清AAT活性测量值仍可能被低估。
