[Enzyme activity of thiamine diphosphate biosynthesis and degradation in the mouse liver in the dynamics of B1 avitaminosis development].

Activities of thiamin pyrophosphokinase (TPK EC 2.7.6.2) and thiamin pyrophosphatase (TPPase EC 3.6.1.6) were studied in liver homogenate supernatants obtained from mouse (female, body weight of 21-23 g) in dynamics of B1 avitaminosis. As compared with controls distinct deficiency of thiamin led a decrease in coenzyme thiamin diphosphate (TPP) down to 15% as well as of transketolase activity (TPP-dependent enzyme) down to 35%, especially during the terminal stage of the avitaminosis; the process was accompanied by cyclic alterations in activity of TPK and TPPase. Within 9 and 17 days of the B1 avitaminosis the activity of TPK increased by 62% and 38% and the activity of TPPase--decreased by 30% and 20%, respectively. Alterations in the enzymatic activity appear to be characteristic for adaptation in response to thiamin deficiency.