抄録
For the fluorometric determination of thiamine, cyanogen bromide as well as potassium ferricyanide is preferably used to oxidize thiamine to thiochrome. Under appropriate conditions, both reagents gave identical results in the determination of a pure thiamine solution. However, tissue thiamine levels determined by cyanogen bromide and ferricyanide methods were not always identical. For muscular tissues such as heart, diaphragm and skeletal muscles, much higher values were obtained by the latter method. On the other hand, synthetic HET was not oxidized by cyanogen bromide, while it was almost quantitatively oxidized to thiochrome by ferricyanide. These results strongly suggested that a considerable amount of HET might be present in these musclar tissues.
To confirm this, about 100g of rat hearts were collected and thiamine compounds were extracted by homogenizing with 0.1 NH2SO4. After deproteinizing with metaphosphoric acid, the extract was treated with Takadiastase to hydrolyze the phosphorylated forms, adsorbed on permutit and the thiamine compounds were eluted with hot KCI-HCI. The eluate was desalted and concentrated by the phenol extraction method. Cellulose powder thin-layer chromatograms developed with 5 different solvent systems showed that two thiamine compounds were contained in the Takadiastase treated heart extract, one of which corresponded to thiamine and the other migrated identically as an authentic sample of HET.
