Schrijver J, Dias T, Hommes F A
Neurochem Res. 1978 Dec;3(6):699-709. doi: 10.1007/BF00965993.
The experiments described in this paper serve as a contribution to the solution of the discrepancies which exist in the assay of ATP:thiamine diphosphate phosphotransferase activity (EC 2.7.4.15), presently in use as a tool for the diagnosis of Leigh's disease (SNE, subacute necrotizing encephalomyelopathy). The results obtained with this phosphotransferase assay can, in part, be explained by the presence of thiamine triphosphate (ThTP) in the preparation of thiamine diphosphate (ThDP) used as a substrate, by the inhibition by ATP of the ThTP phosphohydrolase activity, present in fractions of rat brain homogenates, and by the stimulation by ThDP of the ATPase activity. When [2(-14)C-thiazole]thiamine was used for the synthesis of [14C]ThTP in fractions of rat brain, it was found that after chromatographic separation of thiamine and its phosphates, 14C radioactivity could be demonstrated in the ThTP fractions, even in the absence of an enzyme source. Probably a complex is formed between [14C]thiamine and a phosphate ester which behaves chromatographically as ThTP. It is concluded that the assay system for the measurement of ThTP synthesis in its present form is, in our hands, not suitable for diagnostic purposes.
本文所述实验有助于解决目前作为莱氏病（亚急性坏死性脑脊髓病，SNE）诊断工具的ATP：硫胺二磷酸磷酸转移酶活性（EC 2.7.4.15）测定中存在的差异问题。用这种磷酸转移酶测定法得到的结果，部分可以用作为底物的硫胺二磷酸（ThDP）制剂中存在三磷酸硫胺（ThTP）、ATP对大鼠脑匀浆组分中存在的ThTP磷酸水解酶活性的抑制作用以及ThDP对ATP酶活性的刺激作用来解释。当用[2(-14)C-噻唑]硫胺在大鼠脑组分中合成[14C]ThTP时，发现硫胺及其磷酸盐经色谱分离后，即使在没有酶源的情况下，ThTP组分中也能检测到14C放射性。可能是[1,4C]硫胺与一种在色谱行为上与ThTP相似的磷酸酯形成了复合物。得出的结论是，就我们而言，目前形式的ThTP合成测定系统不适合用于诊断目的。
