Merkulova T I, Kovaleva G K, Kiselev L L
Mol Biol (Mosk). 1987 May-Jun;21(3):769-76.
Incubation of bovine tryptophanyl-tRNA synthetase (EC 6.1.1.2) deprived of endogenous tryptophan, with [14C]ATP and without [gamma-32P]ATP, causes an appearance of radioactivity in protein due to formation of adenylated enzyme, [14C]AMP-E. Examination of the properties of the [14C]AMP-E thus obtained led to the conclusion that AMP is linked to the protein molecule via a macroergetic phosphoanhydride bond. ATP is formed when AMP-E is incubated with PPi. However, no tryptophanyl adenylate formation was observed when AMP-E was treated with tryptophan. The functional role of AMP-E remains obscure.