ENZYMATIC SYNTHESIS OF THIAMINE

Abstract

The enzymes obtained from a cell-free extract of bakers' yeast catalyzed the condensation of the pyrimidine (OMP) and thiazole (Th) moieties of thiamine to form thiamine. ATP and Mg²⁺ were required essentially for the reaction and Mn²⁺ also showed a fair activity. An optimal pH of the reaction was 7.0. Some other pyrimidine compounds which differ from OMP in the chemical structure at the C₅-position of pyrimidine are less active than OMP as the substrates. The enzymatic activations of OMP and Th by ATP in a preliminary step before the condensation were demonstrated.