[Phenylalanine-4-hydroxylase and tyrosine aminotransferase activities in rat liver tissue under different vitamin E content in the organism].

Enzymic activity of tyrosine aminotransferase is unchanged in subcellular fractions of the liver tissue of control, E-hypovitaminotic rats and of the same animals subjected to a single vitamin E administration. Enzymic activity of phenyl alanine-4-hydroxylase in the supernatant fraction determined in the incubation medium without biopterin in animals with E-hypovitaminosis is 39% lower than in the control rats. The coefficient of phenyl alanine-4-hydroxylase activation with biopterin in vitro in E-hypovitaminotic animals is thrice as high as that in the control rats. A single vitamin E administration produces a 1.8-fold decrease in the activation coefficient. The data obtained give reason to suggest the possible influence to vitamin E on the biopterin level in the liver.