Enzymes and ribonucleic acid associated with the incorporation of amino acids into proteins of wheat endosperm

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Abstract
Methods are presented for the separation and purification of amino acyl-RNA synthetases and s-RNA from the protein-body and supernatant preparations of wheat endosperm. The activity of the synthetases was demonstrated by ATP-[p32]pyrophosphate exchange and by the formation of amino acyl-RNA. A method is described for the separation of amino acyl-RNA from enzyme reaction mixtures by chromatography on DEAE-cellulose. The pyrophosphate-exchange reaction catalysed by the synthetases from the protein-body preparation showed an apparent inhibition with added ATP. The pyrophosphate exchange catalysed by the enzymes from the supernatant preparation was almost completely dependent on ATP and stimulated by the addition of ATP. The formation of amino acyl-RNA by enzyme preparations from both the protein-body and supernatant preparations was stimulated by the addition of ATP. An enzyme fraction obtained from the protein-body preparation after treatment with ultrasonic vibration catalysed the incorporation of amino acids into amino acyl-RNA and soluble protein. The localization of enzymes and RNA associated with the initial stages of protein synthesis in the 2 preparations from wheat endosperm, and the significance of these findings in relation to the independent synthesis of storage and cytoplasmic proteins of wheat endosperm, is discussed.