Arginyl-tRNA Synthetase from Brewer's Yeast.

tRNA^Arg and argiuyl-tRNA synthetase have been purified to homogeneity from brewer's yeast by chromatographic methods. Arginyl-tRNA synthetase is a monomeric enzyme with a molecular weight of 72000. Two active forms of the enzyme can be found, they are interconvertible. The more stable conformation is probably the natural one. Arginyl-tRNA synthetase seems to recognize arginine very specifically. No evidence for any proof-reading mechanism could be found. The steady-state mechanism is somewhat different from the types found with arginyl tRNA synthetase from other sources. However, all these results are compatible with a concerted reaction. Simultaneously with the release of AMP or pyrophosphate an allosteric rearrangement occurs. This conversion seems to be determining for the reaction mechanism. [ABSTRACT FROM AUTHOR]