Abstract
Studies on the transport into red blood cells of O-acylthiamine disulfide with kinetic and enzymatic viewpoints are reviewed. A mechanism of at least two-steps is revealed ; one is passive diffusion process due to lipophylic nature of the vitamin derivative and the other is accumulation of free thiamine metabolized from the permeated derivative. The metabolic conversion proceeds via reductive cleavage of the disulfide bond with glutathione and glutathione reductase, followed by deacylation of the resultant O-acylthiamine by an endosomal alliesterase. A schematic mechanism is presented which is generally apllied to accumulative uptake of lipophylic thiamine derivatives.
