Protein synthesis by kinetosomes isolated from the protozoan Tetrahymena

Abstract

An increase in biuret-positive material occurs when kinetosomes isolated from the ciliated protozoan Tetrahymena pyriformis are incubated in a mixture containing amino acids, inorganic phosphorus, uridylic acid, cytidylic acid, guanylic acid, thymine, inosine, MgSO 4, KF, hexose-diphosphate, ATP, pteroylglutamic acid, riboflavin, vitamin B 12, biotin, pyridoxamine, and pantothenic acid. The requirement for vitamin B 12 can be replaced by the Incorporation Factor described by Gale and Folkes but not by cobamide coenzyme, or glycerol. Incorporation of [ 14C]glutamic acid parallels the rate of increase of biuret-positive material, and thus may be taken as an index of synthesis. In addition to glutamate, arginine, histidine, isoleucine, leucine, lysine, phenylalanine, and valine are incorporated into trichloracetic acid-insoluble material. Incorporation is strongly inhibited by DNAase and RNAase but is only slightly inhibited by high concentrations of chloramphenicol.