An Aromatization Mechanism of Inactivation of γ-Aminobutyric Acid Aminotransferase for the Antibiotic <scp>l</scp>-Cycloserine
作者:Gregory T. Olson、Mengmeng Fu、Sharon Lau、Kenneth L. Rinehart、Richard B. Silverman
DOI:10.1021/ja972907b
日期:1998.3.1
The mechanism of inactivation of pig brain γ-aminobutyric acid (GABA) aminotransferase by the antibiotic l-cycloserine was investigated. l-Cycloserine is a time-dependent inactivator of GABA aminotransferase; no enzyme activity returns upon gel filtration or dialysis. Treatment of GABA aminotransferase with [14C]-l-cycloserine, followed by rapid gel filtration, gives enzyme containing l.l equiv of
研究了抗生素l-环丝氨酸对猪脑γ-氨基丁酸(GABA)转氨酶的失活机制。l-环丝氨酸是 GABA 氨基转移酶的时间依赖性灭活剂;凝胶过滤或透析后没有酶活性恢复。用[ 14 C]-1-环丝氨酸处理GABA氨基转移酶,然后快速凝胶过滤,得到含有11当量结合放射性的酶。用酸、碱或尿素进行透析或变性会释放放射性。[3H] 吡哆醛 5'-磷酸 (PLP)-重组 GABA 氨基转移酶与 l-环丝氨酸的失活,随后进行透析或变性也会导致酶的放射性释放。释放的 [14C]- 和 [3H]-标记的加合物均通过 HPLC 迁移,表明失活加合物是 l-环丝氨酸与 PLP 辅酶的缩合产物。通过 HPLC 比较,表明放射性标记的加合物不是 PLP、PMP、PLP 肟或 4-[3-羟基-2-甲基-5-(磷氧甲基)-4-吡啶...