Abstract
1) The production of α-ketoglutaric acid by the washed cells of coli-aerogenes from glucose was observed to be inhibited in the presence of αα'-dipyridyl. Moreover, it was found that both αα'-dipyridyl and O-phenanthroline extremely inhibited the bacterial synthesis of α-ketoglutaric acid from pyruvate, while the consumption of pyruvic acid was not greatly affected and acetic acid or acetoine could be produced even in the presence of these inhibitors. It was thus concluded that inorganic iron would be a kind of cofactor of the enzyme system relating to the synthesis of α-ketoglutaric acid from pyruvate, since these inhibiting actions could be reduced by the addition of inorganic iron such as FeSO4.
2) It was demonstrated that the enzyme preparations such as dried cells and cell-free extracts revealed the ability of synthesizing α-ketoglutaric acid from pyruvate.
3) Lactic acid was found to be a potent precursor in the production of α-ketoglutaric acid by either the washed cells or the growing culture, and the same inhibiting action was again observed by the reagents forming Fe-complex compound.
4) The most presumable mechanism for the synthesis of α-ketoglutaric acid from C3-compound such as pyruvic and lactic acids was discussed.
