Abstract
In order to clarify a metabolic role of pantothenic acid (PaA) derivatives accumulated in rat liver, in the experiments with ^<14>C-pantothenic acid, incorporation of the isotope into the derivatives was determined. The PaA derivatives were extracted from the liver of PaA-deficient rat after administration of ^<14>C-PaA for eight days, then applied on DEAE-cellulose column chromatography. Three radiocative fractions, peak A, B and C were obtained and also detected by microbiological assay with L. arabinosus. It was found that peak A was identified with paA, peak B with 4'-phosphopantetheine and peak C with CoA, respectively, by means of paper chromatography. The ratio of radioactivity per pantothenic acid of the three compounds were 2 : 1 : 1. In the additional labelling experiment, however, the specific radioactivity of peak B (4'-phosphopantetheine) was 2.5 times as much as that of peak C (CoA). This suggests that 4'-phosphopantetheine existed in rat liver acts as a precursor of CoA biosynthesis, but not a decomposition product of CoA.
