Abstract
Thiamine transport systems and their properties, especially their energy coupling mechanisms have been studied comparatively with Escherichia coli cells, Ehrlich ascites tumor cells and brush border membrane vesicles of the guinea pig ileum. In E. coli cells and Ehrlich cells, thiamine was transported against a concentration gradient, and in the brush border membrane vesicles thiamine passed through the membrane by simple diffusion. Active transport of thiamine in E. coli cells and Ehrlich cells coupled directly to an electrochemical potential of H+ and Na+, respectively. These changes in thiamine transport systems are discussed from stand point of evolution of the transports. Key Words: thiamine transport, comparative studies, energy coupling, active transport, simple diffusion
