A STEREOCHEMICAL AND POSITIONAL ISOTOPE EXCHANGE STUDY OF THE MECHANISM OF ACTIVATION OF TYROSINE BY TYROSYL-tRNA SYNTHETASE FROM BACILLUS STEAROTHERMOPHILUS

Article abstract of DOI:10.1016/0040-4020(84)85109-1

Tyrosyl-tRNA synthetase from Bacillus stearothermophilus catalyses the activation of (18)O2-tyrosine by adenosine 5'<(R)α-(17)O>triphosphate with inversion of configuration at Pα.It also catalyses positional isotope exchange in adenosine 5'<β-(18)O2>triphosphate in the presence of tyrosine, but not in its absence or in the presence of the competitive inhibitor tyrosinol.Together these results imply that the enzyme catalyses an associative "in line" displacement of pyrophosphate from Pα of ATP by tyrosine.