Free and nonprotein amino acids of Tetrahymena pyriformis

Paper chromatography was used to determine 20 amino acids and related compounds present in both the free and the nonprotein forms in Tetrahymena pyriformis. The most abundant free amino acids in the cells were found to be glutamic acid, alanine, leucine-isoleucine, glycine, arginine, and lysine. Free methionine, cystine, and tryptophan were present in the smallest quantities. A relatively large proportion of aspartic acid, glycine, and glutamic acid was found in the conjugated form, while nearly all nonprotein arginine and lysine occurred in the free form. In line with values observed in other invertebrates and microorganisms, the [alpha]-amino nitrogen present in the free and the nonprotein forms constituted as high as a fifth and a fourth, respectively, of the total nitrogen of the protozoan cells.A fairly constant ratio of the amino acid content of the whole cell to that of the cellular protein was obtained, which indicated that the amino acid composition of the whole cell reflects that of the cellular protein.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/32514/1/0000605.pd