Nakayama H, Hayashi R
J Bacteriol. 1972 Dec;112(3):1118-26. doi: 10.1128/jb.112.3.1118-1126.1972.
Two types of mutants of Escherichia coli were isolated, one of which (mutant 70-23-107) responded to thiamine pyrophosphate, and the other (mutant 70-23-102) to thiamine monophosphate and thiamine pyrophosphate. They were produced by further mutation of a thiamine auxotroph of E. coli 70-23 with N-methyl-N'-nitro-N-nitrosoguanidine. The parent organism required thiamine because phosphohydroxymethylpyrimidine kinase activity was lacking in this organism, and hydroxymethylpyrimidine pyrophosphate was not permeable through the cell membrane of E. coli. Thiamine, thiamine monophosphate, and thiamine pyrophosphate were all equally active for the parent, whereas mutants 70-23-102 and 70-23-107 lost their ability to grow on thiamine. Both mutants differed only in the growth response to thiamine monophosphate: the former could grow on thiamine monophosphate, whereas the latter could not. Experimental results with the newly isolated mutants indicate that in E. coli the free form of thiamine is not involved in de novo synthesis of thiamine pyrophosphate, but thiamine monophosphate, an exclusive product formed by the reaction between hydroxymethylpyrimidine pyrophosphate and hydroxyethylthiazole monophosphate, is directly phosphorylated to form thiamine pyrophosphate. Exogenous thiamine, on the other hand, is converted to thiamine pyrophosphate via the intermediate formation of thiamine monophosphate.
分离出了两种大肠杆菌突变体，其中一种（突变体70 - 23 - 107）对硫胺素焦磷酸有反应，另一种（突变体70 - 23 - 102）对硫胺素单磷酸和硫胺素焦磷酸有反应。它们是通过用N - 甲基 - N'- 硝基 - N - 亚硝基胍对大肠杆菌70 - 23的硫胺素营养缺陷型进行进一步诱变产生的。亲本菌株需要硫胺素，因为该菌株缺乏磷酸羟甲基嘧啶激酶活性，且羟甲基嘧啶焦磷酸不能透过大肠杆菌的细胞膜。硫胺素、硫胺素单磷酸和硫胺素焦磷酸对亲本的活性相同，而突变体70 - 23 - 102和70 - 23 - 107失去了在硫胺素上生长的能力。这两种突变体仅在对硫胺素单磷酸的生长反应上有所不同：前者能在硫胺素单磷酸上生长，而后者不能。对新分离出的突变体的实验结果表明，在大肠杆菌中，硫胺素的游离形式不参与硫胺素焦磷酸的从头合成，但是硫胺素单磷酸，一种由羟甲基嘧啶焦磷酸和羟乙基噻唑单磷酸反应形成的唯一产物，直接磷酸化形成硫胺素焦磷酸。另一方面，外源硫胺素通过硫胺素单磷酸的中间形成转化为硫胺素焦磷酸。
