STUDY OF THE ROLE OF VITAMIN-E IN THE BIOSYNTHESIS OF UBIQUINONE (Q) AND UBICHROMENOL (QC) IN THE RAT-LIVER

The peculiarities of the biosynthesis of Q in the livers of rats with E deficiency under the influence of alpha-tocopherol and S-adenosylmethionine (SAM) were investigated in vitro. When [C3H3]SAM was used as a precursor, alpha-tocopherol added to the incubation medium induced an appreciable increase in the content of Q, which was accompanied by a sharp increase (by a factor of 2.82) in the relative radioactivity of Q in the liver in comparison with the control samples. Under analogous experimental conditions, using sodium [2-C-14]acetate as a precursor, the addition of alpha-tocopherol led to a 31.4% increase in the content of Q and a 65.2% increase in its relative radioactivity in the experimental liver samples, whereas these indices for QC were essentially unchanged. When SAM was added to the incubation medium it induced a significant increase in the content and relative radioactivity both of Q and of QC in the experimental samples in comparison with the control. Analogous, even more pronounced changes were observed when alpha-tocopherol and SAM were added together. In view of this the role of vitamin E in the activation of methylation reactions at the terminal stages of biosynthesis of Q and QC in the rat liver are discussed.