Aminoacylation of rat liver transfer RNA with L-penicillamine. On the specificity of the aminoacylation reaction.

ABSTRACT

L-]14C]Penicillamine is bound to RNA from rat liver in an in vitro reaction catalyzed by rat liver aminoacyl-tRNA synthetases. Addition of certain naturally occuring amino acids results in a significant decrease of L-penicillamine binding. The most potent inhibitor of this binding is L-valine, followed by L-isoleucine and L-threonine. Amino acids without structural relationship to L-penicillamine in the non-functional part of the molecule, such as L-phenylalanine, are ineffective. Studies on the competition of L-penicillamine and L-isoleucine, respectively, with L-valine demonstrate the high specificity of the aminoacylation reaction. They show that the change of L-penicillamine binding to tRNA Val is considerably lower than that of L-valine.