大腸菌におけるThiamine Propyl Disulfideのとりとみについて

概要

論文の詳細を見る
Properties of the uptake system of thiamine propyl disulfide (TPD) have been investigated in Escherichia coli (J. Vitaminol. 16,39 (1970)). TPD was taken up by the cells of E. coli and was accumulated mostly as thiamine diphosphate (TDP), but not as TPD. The time course of TPD uptake was similar to that in thiamine uptake, but the rate and amount of TDP accumulation in the cells were always less than those in thiamine uptake. The TPD uptake was found to be an energy-, temperature-and pH-dependent process, which followed Michaelis-Menten kinetics ; apparent Km was 3.0×10^<-6>M. Pretreatment of the cells with N-ethylmaleimide resulted in inhibition of the rate of TDP accumulation much stronger in TPD uptake than that in thiamine uptake. A thiamine transport-negative mutant of E. coli (KG 900), which is defective in a thiamine specific carrier protein and contains a normal level of thiamine kinase, could not accumulate TDP in the cells when incubated with TPD. From these results the process of TPD uptake in E. coli is different from that in red cells which take up TPD by simple diffusion or in yeast cells which do not take up TPD. It is concluded that, in E. coli, TPD is transported into the cells through the thiamine specific uptake system after reduction to thiamine on the surface of the cell membrane. (Received June 17,1970)
日本ビタミン学会の論文
1970-09-25