Metabolism of Benzimidazole in Wheat: I. Formation of Benzimidazole Nucleotide

An enzyme, probably benzimidazole nucleotide:pyrophosphate phosphoribosyl transferase, has been demonstrated in the 33–65% (NH4)2SO4fraction of wheat embryos. The enzyme was assayed indirectly by the apparent inhibition of the analogous orotidine-5′-phosphate pyrophosphorylase caused by benzimidazole competing with orotate for P-ribosyl-PP. Both enzymes were in the same fraction. The reaction product, benzimidazole nucleotide, was separated by paper electrophoresis and thin-layer and column chromatography, and was identified by chemical and spectral analysis. Kinetin showed similar competitive behavior.