Effect of biotin on the bacterial formation of glutamic acid. I. Glutamate formation and cellular permeability of amino acids

It has been shown that glutamic acid is formed in the growing culture medium of Brewbacterium flavum, a biotin requiring bac-terium, when a certain subthreshold concent-ration of biotin is given {1-3). Considerable knowledge has now accumulated concerning the paths of synthesis of glutamic acid from ammonium salt and some carbon sources in B.flamtm (4-15). Thus, the studies using some radioactive compounds as well as the inhibi-tion experiments and the demonstration of the enzymes involved in the glutamate for-mation have indicated the probable synthetic pathway from glucose of glutamic acid as the Embden-Meyerhof pathway followed by the modified TCA cycle with an additional glyoxylate bypass. However, there has been little knowledge concerning the biochemical function of biotion on the glutamate forma-tion. Since our preliminary studies show that the cells grown in a biotin-poor medium can form glutamate also in the resting state as well as in the growing state while those grown in a biotin-rich medium cannot so, it is of interest to compare the biochemical pro-perties of these resting cells with each other. The present paper deals with the effect of biotin concentration in the culture medium on the glutamate forming ability of the wash-ed cells and on the cellular permeability of amino acids