Free and nonprotein amino acids of Tetrahymena pyriformis.

In a previous study (l), the composition of total cellular amino acids of the ciliated protozoan, Tetrahymena pyriformis (formerly, T. geleii), was presented together with other pertinent data concerning the nitrogen metabolism of this organism. The present investigation was undertaken to obtain information on the free and nonprotein amino acids of this protozoan cell, inasmuch as the nonprotein nitrogen constitutes an unusually large fraction of the total nitrogen. These data make possible an evaluation of the relationship between the amino acid composition of the whole cell and that of the cellular protein. In addition, they pro/ vide a basis for comparison with results of similar investigations on other : organisms.