The assimilation of amino-acids by bacteria. 11. The relationship between accumulation of free glutamic acid and the formation of combined glutamic acid in Staphylococcus aureus

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Abstract
Free glutamic acid accumulates within the cells of washed suspensions of S. aureus incubated in the presence of glucose and glutamic acid. Some of the amino acid is metabolized, but no formation of combined glutamate occurs. In the presence of a complete and balanced mixture of amino acids, the accumulation of free glutamic acid within the cells decreases and may cease; the amt. of glutamic acid withdrawn from the medium in a given time is markedly less than that withdrawn when glutamic acid is the only amino acid present, and an increase occurs in the amt. of combined glutamate in the cells. The rate at which the combined glutamate of the cells increases can be correlated with the initial concn. of free glutamic acid within the cells. If the external glutamic acid concn. is raised to approx. 100 times that of the other components of the amino acid mixture, some accumulation of free glutamic acid occurs, but the formation of cellular combined glutamate is suppressed. Whether glutamic acid accumulates in the free state within the cell or enters into combination within the cell depends upon the balance between glutamic acid and the other amino acids in the medium.[long dash]Auth. summ.