METABOLIC ACTIVITIES OF MONONUCLEOSIDES ON THE ACTIVATION OF LIVER-PYRUVATE OXIDASE SYSTEM RELATING TO THIAMINE DIPHOSPHATE.

Abstract

1. The effects of pyrimidine mononucleotides on liver-pyruvate oxidase system was studied, and it was found that the addition of UMP or CMP resulted in similar increase of the enzyme activity. The metabolic fate of the nucleotides in the reaction mixture was quite similar to the case of inosine-5′-phosphate.FIG. 2 Effects of Mononucleotides on the Activation of Thiamine Diphosphate in Rat Liver-Pyruvate Oxidase SystemFIG. 3 Paper Chromatograms of the Metabolic Products of Various Mononucleotides in the Reaction Mixture of Rat Liver-Pyruvate Oxidase SystemSolvent I, n-butanol-acetic acid-water (12:3:5); Solvent II, water (pH 5.2 to 5.5); Solvent III, n-butanol (water-saturated); Solvent IV, pyridine-n-butanol-water (1:1:1).Ad-R, adenosine; Ad, adenine; G-R, guanosine; G, guanine; I-R, inosine; U-R, uridine; U, uracil; C-R, cytidine; C, cytosine.2. The effects of various nucleosides on the enzyme activity were also tested, and the degradation products were estimated by paper chromatography. The metabolic fates of the mononucleosides were found to be quite similar to the case of inosine, and the reappearance of the mononucleosides was noticed after addition of both the corresponding bases and D-ribose.