[Content of free and bound thiamine diphosphate in the liver hyaloplasm of vitamine B1 deficient rats].

The amount of free and protein-bound thiamin diphosphate (TDP) in the liver hyaloplasm of B1 vitamin deficient rats has been measured. In the norm the content of protein-bound TDP remains stable (4.5--4.7 micrograms/g tissue) and does not grow upon thiamin injections. The level of the free coenzyme varies appreciably: in the B1-avitaminotic state the content of free TDP decreases, and in the B1-saturated condition it may exceed the norm 4 times. In the liver this enzyme occurs only as a holoenzyme. In case of B1 vitamin deficiency in the diet the transketolase apoform cannot be detected in the liver. A new model for rapid generation of B1-avitaminosis characterized by a significantly lower level of free and bound TDP is described.