C-13 NMR-STUDIES OF HISTIDINE FERMENTATION WITH A CORYNEBACTERIUM-GLUTAMICUM MUTANT

13C NMR spectroscopy was applied to studies on histidine biosynthesis in Corynebacterium glutamicum N-730, a histidine producing mutant. When it was cultured in a medium containing [1-13C]glucose as the carbon source, the 13C isotopomer was abundantly incorporated into C-6 (28 atom%) and C-1 (21%), and to a lesser extent into C-5 (7%) of the histidine accumulated. The high incorporation into C-6 was explained as being due to that most of the one-carbon unit for histidine biosynthesis is derived from serine. On the bases of this view and the 13C population value at C-6, the contributions of the Embden-Meyerhof and hexose monophosphate pathways to the histidine production were calculated to be 56 and 44%, respectively. The significance of the label incorporation into C-1 and C-5 was discussed.