Abstract
Thiamine diphosphate(TDP), when incubated with Lactobacillus fermenti harvested from thiamine-poor broth, was more effectively uptaken by cells than thiamine. Practically no free thiamine was found in cells during the process of thiamine-uptake. Glucose is essential for thiamine-uptake which was proved to be active transport, because typical inhibition by DNP or NaF but no inhibition by ouabain had been shown. Pyrithiamine or Amprolium showed stronger inhibition against uptake of TDP by cells than that of thiamine. When ^<32>P-TDP was incubated with Lactobacilli cells, uptaken ^<32>P was found to coincide with uptaken thiamine. As such phosphatase inhibitors as molybdate and phosphate had no inhibition to uptake of TDP by cells. TDP seems to be uptaken by Lactobacilli as TDP de novo, not as free thiamine after hydrolysis by phosphatase. (Received Nov. 24,1970)
