1. When Brevibacterium fiavum No. 2247 grew in a biotin-rich medium, L-glutamate was not formed from glucose nor acetate in the washed cells as well as in the growing culture, whereas it was formed in the washed cells as well as in the growing culture when this bacterium grew in a biotin-poor medium.
2. Although L-aspartic-α-ketoglutaric transaminase activity of cell-free extracts was not affected by the biotin concentration in the culture medium, that of the washed cells was greatly affected and, that is, the activity of the washed cells grown in a biotin-rich medium was negligibly small while it was recovered by treating the cells with the detergent substances. The effect of biotin on the transaminase activity as well as on the glutamate forming ability of the washed cells depended on the carbon source on which the cells had grown.
3. The amount of the intracellular amino acids in the cells grown in a biotin-poor medium was less than that in the cells grown in a biotin-rich medium. In the former case, the cells released the intracellular amino acids almost completely upon washing with a buffer solution, but not in the latter case, where the release of those was observed only when the cells were incubated with detergent substances.
4. When the cells were incubated with amino acids and with α-ketoglutaric acid, net incorporation into the cells was observed in the cells grown in a biotin-poor medium but not in the cells grown in a biotin-rich medium.
5. From these results, one of the main effects of biotin on the metabolic ability of the cells seems to exist in the cellular permeability of amino acids and it can also explain the effect on the glutamate forming ability of the cells.
The authors are indebted to Dr. H. Oeda and Dr. Y. Tsuchiya of our laboratory for their interest and encouragement during the course of this work.