[A method of determining the concentration of thiamine].

The rate of the production of thiazole, the first product of the reaction, catalyzed by thiaminase I (EC 2.5.1.2) from Anodonta cygnea muscles is characterized by an initial flash-up explained by a considerable difference in the rates of the enzyme-substrate complex formation and its further transformation. Basing on this phenomenon, a new method for measuring the total thiamine in vitro and in biological material has been developed. Optimal conditions for thiamine measurements in the blood and urine have been selected.