THE EFFECT OF X-IRRADIATION ON THE ACTIVATION OF AMINO ACIDS IN NUCLEI FROM RAT THYMUS GLAND

Publisher Website
Google Scholar
Abstract
Amino acid-activating enzymes were extracted with an ionic medium from nuclei prepared in iso-osmotic sucrose. Pyrophosphatase activity was found in this enzyme preparation. Amino acyl hydroxamate formation was measured spectrophotometrically and also by isotopic methods that have the advantage of greater sensitivity. An electrophoretic isotopic method was used to study the activation of acidic, basic and neutral amino acids. Amino acyl hydroxamate formation is critically dependent on the concentration of amino acids present. The activation of 8 amino acids was demonstrated. Activating enzymes extracted from nuclei X-irradiated in vitro had a decreased activating ability, but irradiation of the isolated activating enzymes caused no inhibition.