1956] Free and Nonprotein amino acids of Tetruhymena pyriformis. Archives of Biochemistry and Biophysics 62:707−707

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 nitro-gen metabolism of this organism. The present investigation was under-taken 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. EXPERIMENTAL PROCEDURES The identical cell preparation that was obtained by growing the peptone strain of T. pyrijormis in a peptone medium, and designated as P-P in a previous study (1)) was used in this investigation. Approximately 100 mg. of this cell preparation was suspended in 10 ml. of distilled water and dialyzed (2) against 20 ml. of dis-tilled water at 4“C. for 16 hr. Cellulose casing (27/32, Nojax, Visking Corporation) was used as the dialyzing membrane. An aliquot of the dialyzate was desalted with the apparatus of Astrup and associates (3) for 15 min. The desalted dialyzate was dried in vacua, and taken up in a small volume of 10 % 2-propanol. This con